Update PR workflow to include unit tests job

Also includes JS linting, checking the strings are properly
extracted for translation, etc.

Some of these may be split to separate jobs in future but are
kept this way to reuse the existing script responsible for
running the unit test job on prow.

.github/workflows/pr.yml

@@ -4,7 +4,6 @@ permissions:
   contents: read
 
 on:
-  workflow_dispatch:
   pull_request:
     branches: ["main"]
 
@@ -50,3 +49,20 @@ jobs:
         working-directory: ${{ github.workspace }}/src/github.com/tektoncd/dashboard
         run: |
           ./test/presubmit-tests.sh --build-tests
+
+  unit-tests:
+    name: Unit tests
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Harden runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        with:
+          egress-policy: audit
+
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Run tests
+        run: |
+          ./test/presubmit-tests.sh --unit-tests