🐛 Add back seeds for config import

[tuliren]

What

• This PR resolves Import Configuration removes all available connectors #5187.
• When importing the configs, the importer does not import the source and destination definitions from the archive file. Instead, it reads from the seed to try to get the latest definitions for any connector definitions unused by the user.
• However, the seeds are no longer read in the recent refactoring (refactor import / export endpoints to use the same code path as auto … #4976). So when configs are imported, all of the unused connector definitions are dropped.

How

• importData is replaced with importDataWithSeed to always read the seeds.
• Currently the new change is not tested. I will try to unit test it in a separate PR, because the testing is complicated.
• Also the seeds logic will be cleaned up when I work on Load initial seed configs from YAML files and get rid of the init container #4890.

Recommended reading order

1. ConfigDumpImporter.java
2. The rest.

[tuliren]

This is the root cause of the bug.

[cgardens]

thank you!

[tuliren]

I just updated the PR description. The unit test for this change is complicated. I will try to test it in a separate PR. If that's not trivial, the seeding logics will be refactored very soon any way.

[cgardens]

legit. i'm definitely cool with it if you want to do less test writing now if you know you are about to refactor it and think that test writing then will be more efficient.