🐞 Fix db config persistence initialization

[tuliren]

What

• When the local config directory exists, ConfigSeedProvider will always return the file system persistence as the seed provider and load into the database config persistence, which will roll back unused connector definitions, as reported in Connector versions are rolled back after Airbyte server is upgraded #5954.
• This bug is introduced because:
  • There is no unit test for ConfigSeedProvider.
  • Initially the ConfigPersistence#loadData method is only purposed to initialize the persistence. However, later on it is patched to update the connector definitions as well. The method itself is tested, however, the seed persistence fed into this method is not because of the first bullet point, resulting in this bug.
  • In addition, connector definition is always updated when the image tag is different in updateConnectorDefinitions. This is ok if the seed is always the latest. However, because old configs can be fed into the loadData method, without the version check, the connector will always get rolled back if it is not used. Should there be a version check, we can have a second layer of defense.

How

• Move both the seed provider logic and the initialization logic to a new initialize method. This method is tested and can guard against stale seed being used to initialize the persistence.
• A second layer of defense is added in updateConnectorDefinitions that only updates a connector if there is a new version.

Recommended reading order

1. DatabaseConfigPersistence.java
2. The rest.