unified-pipeline / openapi-alps PR Summary incorrectly adds `SuppressionReviewRequired`

[Teams post by Zhenhua Hu](https://teams.microsoft.com/l/message/19:4f661242c446452e895359cc3ef45125@thread.tacv2/1710739987988?tenantId=72f988bf-86f1-41af-91ab-2d7cd011db47&groupId=0cab4ce9-7691-42ae-82e3-460d4346a710&parentMessageId=1710739987988&teamName=ARM%20API%20Reviewers&channelName=ARM%20linter%20rules&createdTime=1710739987988)

Affected PR:
- https://github.com/Azure/azure-rest-api-specs-pr/pull/15561/files

ADO build log:
- https://dev.azure.com/azure-sdk/internal/_build/results?buildId=3605255&view=logs&j=d6a48a56-e996-55ca-2302-c3a9a7be685b&t=f4162ac4-a5be-580e-39db-db0d6209bd6a

README diff:
- https://github.com/Azure/azure-rest-api-specs-pr/pull/15561/files#diff-082d114eea0a501f98601de0e2ad319db2a01dc0fc39cdbbb905bd40fbbcbc69

Relevant code:
- [processSuppression](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_git/openapi-alps?path=public/rest-api-specs-scripts/src/prSummary.ts&version=GCe49781cc9ba95eef9747fb456129d3fdc5bac0bd&line=164&lineEnd=185&lineStartColumn=1&lineEndColumn=2&_a=contents)
- [getSuppressions](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_git/openapi-alps?path=public/rest-api-specs-scripts/src/prSummary.ts&version=GCe49781cc9ba95eef9747fb456129d3fdc5bac0bd&line=187&lineStartColumn=10&lineEndColumn=25&_a=contents)

According to `getSuppressions` only `directive` and `suppressions` elements of `README` are processed for determining suppression diff. This PR doesn't touch any of them and yet adds the label.