Update Cloud Run Resource to make containerPort be optional

[ccogan-lh]

Updating Cloud Run resource to mark containerPort as optional. Discovered this when I tried to specify h2c only and let GCP tell my app which port to use.

See documentation here - https://cloud.google.com/run/docs/reference/rest/v1/Container#ContainerPort

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).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• 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).
• Ran relevant acceptance tests (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)

cloudrun: updated `containers.ports.container_port` to be optional instead of required on `google_cloud_run_service`

[modular-magician]

Hello! I am a robot who works on Magic Modules PRs.

I have detected that you are a community contributor, so your PR will be assigned to someone with a commit-bit on this repo for initial review.

Thanks for your contribution! A human will be with you soon.

@megan07, please review this PR or find an appropriate assignee.

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 2 files changed, 10 insertions(+), 10 deletions(-))
Terraform Beta: Diff ( 2 files changed, 10 insertions(+), 10 deletions(-))
TF Validator: Diff ( 2 files changed, 10 insertions(+), 10 deletions(-))

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))
Terraform Beta: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))
TF Validator: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))

[megan07]

LGTM! Thanks!

[megan07]

/gcbrun

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))
Terraform Beta: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))
TF Validator: Diff ( 2 files changed, 8 insertions(+), 8 deletions(-))