[FLINK-38859] Do not apply minimum job vertex parallelism for whole job in native mode

[gyfora]

What is the purpose of the change

There is a logic currently that applies the minimum vertex override as job parallelism which was added to somewhat support autoscaling in standalone mode in a more predictable way. This however is not limited to standalone mode and can lead to strange outcomes in native mode when the user manually sets parallelism overrides.

Brief change log

• Limit the parallelism change logic to standalone mode
• Tests

Verifying this change

Unit tests added

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changes to the CustomResourceDescriptors:no
• Core observer or reconciler logic that is regularly executed: no

Documentation

• Does this pull request introduce a new feature? no