Do not check consumer_groups if the offset is invalid

[FlorentClarret]

What does this PR do?

Do not check consumer_groups if the offset is invalid

Motivation

• QA for Improve performance of check #15106
• We don't need to test the regex if the offset is not valid

Additional Notes

• This will improve performance for this check in some cases with a very large regex and a high number of groups
• This is a refactor, existing tests are enough to validate everything is still working

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached
• If the PR doesn't need to be tested during QA, please add a qa/skip-qa label.

[codecov]

Codecov Report

Merging #15237 (9593f2b) into master (f2bcac8) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Flag	Coverage Δ
kafka_consumer	93.30% <100.00%> (+0.15%)	⬆️

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[github-actions]

Test Results

    8 files      8 suites   6m 33s ⏱️
  48 tests   48 ✔️ 0 💤 0 ❌
196 runs  192 ✔️ 4 💤 0 ❌

Results for commit 9593f2b.

[yzhan289]

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