fix(kubernetes-client-api): TokenRefreshInterceptor doesn't overwrite existing OAuth token with empty string

[manusa]

Description

Fix #4442
fix(kubernetes-client-api): TokenRefreshInterceptor doesn't overwrite existing OAuth token with empty string

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change
• Chore (non-breaking change which doesn't affect codebase;
  test, version modification, documentation, etc.)

Checklist

• Code contributed by me aligns with current project license: Apache 2.0
• I Added CHANGELOG entry regarding this change
• I have implemented unit tests to cover my changes
• I have added/updated the javadocs and other documentation accordingly
• No new bugs, code smells, etc. in SonarCloud report
• I tested my code in Kubernetes
• I tested my code in OpenShift

[manusa]

Some other test might be messing up the new tests.
I can't reproduce the test failure locally even if I run the suite continuously thousands of times either via Maven or the IDE.