Prevent creation of RepositoryAttribute duplicates by accepting a ReadAttributeRequestItem

[Milena-Czierlinski]

Readiness checklist

• I added/updated tests.
• I ensured that the PR title is good enough for the changelog.
• I labeled the PR.
• I self-reviewed the PR.

[codecov]

Codecov Report

Attention: Patch coverage is 84.48276% with 9 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ribute/AcceptReadAttributeRequestItemParameters.ts	40.00%	8 Missing and 1 partial ⚠️

Files with missing lines	Coverage Δ
...readAttribute/ReadAttributeRequestItemProcessor.ts	92.43% <100.00%> (+0.69%)	⬆️
...ribute/AcceptReadAttributeRequestItemParameters.ts	65.47% <40.00%> (-5.54%)	⬇️

[jkoenig134]

LGTM