**This PR removes the old, custom Java serialization support for TestIdentifier. The SerializedForm inner class has been deleted. **

What changed

1. Deleted the SerializedForm inner class from TestIdentifier.
2. TestIdentifier keeps implementing Serializable.
3. Added @SuppressWarnings("serial") to the Set<TestTag> tags, as declared type is Set (not Serializable); actual instances are Serializable.
4. Removes unused imports
5. Updated tests:
   • Removed initialVersionCanBeDeserialized() test.
   • Removed the corresponding resource: 'serialized-test-identifier'
   • Added a parameterized Test case currentVersionCanBeSerializedAndDeserialized_withVariousTagCounts(int tagCount) to test the number of tags to be serialized.

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes