Make google_notebooks_instance metadata field updatable

[melinath]

Fixes hashicorp/terraform-provider-google#14403.

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Generated Terraform providers, and ran make test and make lint in the generated providers to ensure it passes unit and linter tests.
• Ran relevant acceptance tests using my own Google Cloud project and credentials (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

notebooks: added update-in-place support for `google_notebooks_instance.metadata` field

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

Terraform GA: Diff ( 1 file changed, 150 insertions(+))
Terraform Beta: Diff ( 1 file changed, 28 insertions(+), 12 deletions(-))
TF Conversion: Diff ( 2 files changed, 3 insertions(+), 3 deletions(-))

[modular-magician]

Tests analytics

Total tests: 2740
Passed tests 2449
Skipped tests: 283
Affected tests: 8

Action taken

Found 8 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

TestAccNotebooksInstance_update|TestAccAlloydbBackup_missingLocation|TestAccComputeFirewallPolicyRule_multipleRules|TestAccApigeeKeystoresAliasesKeyCertFile_apigeeKeystoresAliasesKeyCertFileTestExample|TestAccAlloydbCluster_missingLocation|TestAccApigeeKeystoresAliasesPkcs12_ApigeeKeystoresAliasesPkcs12Example|TestAccDataSourceAlloydbLocations_basic|TestAccDataSourceGoogleFirebaseAndroidAppConfig

Get to know how VCR tests work

[modular-magician]

Tests passed during RECORDING mode:
TestAccAlloydbBackup_missingLocation[Debug log]
TestAccApigeeKeystoresAliasesKeyCertFile_apigeeKeystoresAliasesKeyCertFileTestExample[Debug log]
TestAccAlloydbCluster_missingLocation[Debug log]
TestAccApigeeKeystoresAliasesPkcs12_ApigeeKeystoresAliasesPkcs12Example[Debug log]
TestAccDataSourceAlloydbLocations_basic[Debug log]
TestAccDataSourceGoogleFirebaseAndroidAppConfig[Debug log]

Tests failed during RECORDING mode:
TestAccNotebooksInstance_update[Error message] [Debug log]
TestAccComputeFirewallPolicyRule_multipleRules[Error message] [Debug log]

Please fix these to complete your PR
View the build log or the debug log for each test

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

Terraform GA: Diff ( 2 files changed, 204 insertions(+), 1 deletion(-))
Terraform Beta: Diff ( 2 files changed, 82 insertions(+), 13 deletions(-))
TF Conversion: Diff ( 2 files changed, 3 insertions(+), 3 deletions(-))

[modular-magician]

Tests analytics

Total tests: 2741
Passed tests 2450
Skipped tests: 283
Affected tests: 8

Action taken

Found 8 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

TestAccNotebooksInstance_update|TestAccDataSourceGoogleFirebaseAndroidAppConfig|TestAccComputeFirewallPolicyRule_multipleRules|TestAccDataSourceAlloydbLocations_basic|TestAccApigeeKeystoresAliasesKeyCertFile_apigeeKeystoresAliasesKeyCertFileTestExample|TestAccAlloydbCluster_missingLocation|TestAccAlloydbBackup_missingLocation|TestAccApigeeKeystoresAliasesPkcs12_ApigeeKeystoresAliasesPkcs12Example

Get to know how VCR tests work

[modular-magician]

Tests passed during RECORDING mode:
TestAccNotebooksInstance_update[Debug log]
TestAccDataSourceGoogleFirebaseAndroidAppConfig[Debug log]
TestAccDataSourceAlloydbLocations_basic[Debug log]
TestAccAlloydbCluster_missingLocation[Debug log]
TestAccAlloydbBackup_missingLocation[Debug log]

Tests failed during RECORDING mode:
TestAccComputeFirewallPolicyRule_multipleRules[Error message] [Debug log]
TestAccApigeeKeystoresAliasesKeyCertFile_apigeeKeystoresAliasesKeyCertFileTestExample[Error message] [Debug log]
TestAccApigeeKeystoresAliasesPkcs12_ApigeeKeystoresAliasesPkcs12Example[Error message] [Debug log]

Please fix these to complete your PR
View the build log or the debug log for each test

[roaks3]

Overall LGTM. I had a question regarding the tests, but I suspect that there is either a verification step I missed, or adding one would be more effort than it's worth.

[roaks3]

Am I understanding this correctly that we aren't ever checking that the metadata is updated on the server?

[melinath]

yes. The field is marked as ignore_read on the resource, so we never check what the value on the server is. I had to add it here because I introduced it as a new field in this test.

I suspect that we would not use ignore_read like this if implementing the resource today - but fixing that wouldn't be trivial and is outside of the scope of the ticket. In the future I think we'd want to do something similar to hashicorp/terraform-provider-google#14293.