allow src/dest validation to be skipped for tombstone entries

[colesnodgrass]

What

• fix Cannot delete a source due to configuration error #16113
  • if an source or destination somehow end up with an invalid configuration, don't validate it if it's being deleted
• replace for loop in SourceHandler with a stream/filter/forEach

How

• update private method statefulUpdateSecrets to accept an additional boolean validate parameter which is used to determine if JsonSchemaValidator.ensure should be called
• add tests to validate that JsonSchemaValidator.ensure is called correctly

Recommended reading order

1. x.java

[jdpgrailsdev]

This feels like the conditional logic should be internal to the SecretsHelper. Otherwise, it requires the caller to know when to use the different methods. Because the oldConfig is an optional, the logic to determine how to split the config could be codified inside the method, simplifying the call from the client code (e.g. here).

[colesnodgrass]

The only part that differs logically is the method from before are these three lines:

    if (validate) {
      validator.ensure(spec.getConnectionSpecification(), fullConfig);
    }

Everything else, including the section you called out, was existing logic that I slightly cleaned up to remove some duplicate code. I agree with what you're saying though and will make that change as part of this PR.

[jdpgrailsdev]

@colesnodgrass No worries...it was hard to tell if it was pre-existing. Fine to do that cleanup in a follow-on PR if that's easier.

[colesnodgrass]

@jdpgrailsdev I think I will do it in a follow-up PR, I started pulling on this thread to clean this up and it started pulling in other unrelated code as well.

[jdpgrailsdev]