[ISSUE #10835] fix(common): reject malformed topic config atomically

[beautyarbutin]

Which Issue(s) This PR Fixes

• Fixes TopicConfig.decode mutates state or throws for malformed config #10835

Brief Description

TopicConfig.decode() previously assigned topicName before parsing the mandatory numeric and enum fields. Invalid input could therefore throw and leave the existing object partially mutated.

Parse all mandatory fields into local variables first, return false on invalid numeric or filter-type values, and update the object only after all mandatory fields are valid. Regression coverage verifies truncated input and each invalid mandatory field while comparing the complete original object state.

This follows up on #10845, which was closed without being merged.

How Did You Test This Change?

• mvn -B -ntp -pl common clean -DskipITs -Dtest=TopicConfigTest -Dspotbugs.skip=true test
• TopicConfigTest: 4 tests passed
• Checkstyle: 0 violations

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 49.62%. Comparing base (78b96bc) to head (3552575).

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #11210      +/-   ##
=============================================
- Coverage      49.71%   49.62%   -0.10%     
+ Complexity     14346    14314      -32     
=============================================
  Files           1390     1390              
  Lines         103190   103197       +7     
  Branches       13493    13493              
=============================================
- Hits           51301    51209      -92     
- Misses         45721    45791      +70     
- Partials        6168     6197      +29     

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