[FLINK-39432] Add option to delete with session running session jobs

[gyfora]

What is the purpose of the change

Add configuration to allow deletion of session clusters without blocking on session jobs. This allows the deletion and upgrade of clusters even in cases when the jobs cannot be deleted for some reason and may be desirable in some use-cases (where the session cluster upgrade is more important than the job health). The new config is disabled by default to preserve the existing behaviour

Brief change log

• Introduce new config
• New tests

Verifying this change

Unit and manual testing

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? yes
• If yes, how is the feature documented? generated

[gaborgsomogyi]

This failed, maybe flaky?

Error:    RestApiMetricsCollectorTest.testJmMetricCollection:187->lambda$testJmMetricCollection$4:189->assertMetricValueIs:319