Removed similar issues bot GitHub Action (#33909)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request

Remove the GitHub action version of the Similar issues bot. This was the
prototype version, we have now developed a more robust version in
partnership with GitHub (currently in the form of a GitHub app) and are
installing that on the repo instead.

.github/workflows/similarIssues.yml

@@ -1,33 +0,0 @@
-name: GitGudSimilarIssues comments
-
-on:
-  issues:
-    types: [opened]
-
-jobs:
-  getSimilarIssues:
-    runs-on: ubuntu-latest
-    outputs:
-      message: ${{ steps.getBody.outputs.message }}
-    steps:
-      - id: getBody
-        uses: craigloewen-msft/GitGudSimilarIssues@main
-        with:
-          issueTitle: ${{ github.event.issue.title }}
-          issueBody: ${{ github.event.issue.body }}
-          repo: ${{ github.repository }}
-          similarityTolerance: "0.75"
-  add-comment:
-    needs: getSimilarIssues
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-    if: needs.getSimilarIssues.outputs.message != ''
-    steps:
-      - name: Add comment
-        run: gh issue comment "$NUMBER" --repo "$REPO" --body "$BODY"
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          NUMBER: ${{ github.event.issue.number }}
-          REPO: ${{ github.repository }}
-          BODY: ${{ needs.getSimilarIssues.outputs.message }}