ci: Add reusable unit test workflow (no-changelog) (#7159)

Github issue / Community forum post (link here to close automatically):

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

.github/workflows/units-tests-dispatch.yml

@@ -0,0 +1,39 @@
+name: Runs unit tests for a given ref
+
+on:
+  workflow_dispatch:
+    inputs:
+      ref:
+        description: 'GitHub ref to test.'
+        required: false
+        default: 'master'
+        type: string
+      prNumber:
+        description: 'PR number to run tests for.'
+        required: false
+        type: number
+
+jobs:
+  prepare:
+    name: Prepare
+    runs-on: ubuntu-latest
+    outputs:
+      branch: ${{ steps.compute-branch.outputs.branch }}
+    steps:
+      - name: Compute branch
+        id: compute-branch
+        run: |
+          BRANCH_NAME=""
+          if [[ "${{ inputs.prNumber }}" != "" && "${{ inputs.prNumber }}" != "null" ]]; then
+            BRANCH_NAME="refs/pull/${{ inputs.prNumber }}/merge"
+          else
+            BRANCH_NAME="${{ inputs.ref }}"
+          fi
+          echo "branch=$BRANCH_NAME" >> $GITHUB_OUTPUT
+
+  unit-test:
+    name: Unit tests
+    needs: prepare
+    uses: ./.github/workflows/units-tests-reusable.yml
+    with:
+      ref: ${{ needs.prepare.outputs.branch }}