Add back repo checkout step without path prefix

The checkout step is still needed to get the source code,
but without path: main so it checks out to workspace root.
This is consistent with the removal of all main/ path prefixes.

Co-authored-by: Balackburn <93828569+Balackburn@users.noreply.github.com>

.github/workflows/buildapp.yml

@@ -59,6 +59,12 @@ jobs:
       contents: write
 
     steps:
+      - name: Checkout
+        uses: actions/checkout@v6.0.1
+        with:
+          ref: ${{ github.event.inputs.commit_id || github.ref }}
+          submodules: recursive
+
       - name: Install Dependencies
         run: brew install ldid dpkg make jq