fix: build failing at test

[rkpattnaik780]

The build is currently failing as flag description for topic retention byte ends with a fullstop.

Verification Steps

The build GitHub action should pass.

--- FAIL: Test_ValidateCommandsUsingCharmilValidator (0.01s)
    validator_test.go:56: validationErr was not empty, got length: 2; want 0
    validator_test.go:61: PUNCTUATION_RULE: cmd rhoas kafka topic create: full stop in the flag usage
    validator_test.go:61: PUNCTUATION_RULE: cmd rhoas kafka topic update: full stop in the flag usage

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation change
• Other (please specify)

Checklist

• Documentation added for the feature
• CI and all relevant tests are passing
• Code Review completed
• Verified independently by reviewer