chore: aggregate test results for required statuses (#592)

Status check names include matrix elements.  This means that required status names would have to change if any of those matrix elements changed in the future.

This change aggregates these checks into a single status check with a constant name, suitable for use as a required status.

Fixes https://dfinity.atlassian.net/browse/SDK-582

.github/workflows/e2e-tests.yml

@@ -47,3 +47,13 @@ jobs:
         env:
           CI: true
           REPLICA_PORT: 8000
+
+  aggregate:
+    name: e2e:required
+    if: ${{ always() }}
+    needs: [ test ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: check e2e test result
+        if: ${{ needs.test.result != 'success' }}
+        run: exit 1

.github/workflows/mitm.yml

@@ -63,3 +63,13 @@ jobs:
           REPLICA_PORT: 8888
           MITM: true
         run: npm run mitm --workspaces --if-present
+
+  aggregate:
+    name: mitm:required
+    if: ${{ always() }}
+    needs: [ test ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: check e2e test result
+        if: ${{ needs.test.result != 'success' }}
+        run: exit 1

.github/workflows/prettier.yml

@@ -28,3 +28,13 @@ jobs:
       - run: npm install -g npm
       - run: npm install prettier pretty-quick
       - run: npm run prettier:check
+
+  aggregate:
+    name: format:required
+    if: ${{ always() }}
+    needs: [ test ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: check e2e test result
+        if: ${{ needs.test.result != 'success' }}
+        run: exit 1

.github/workflows/unit-tests.yml

@@ -42,3 +42,13 @@ jobs:
       - run: npm run test
         env:
           CI: true
+
+  aggregate:
+    name: unit:required
+    if: ${{ always() }}
+    needs: [ test ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: check e2e test result
+        if: ${{ needs.test.result != 'success' }}
+        run: exit 1