Hopefully fix issues running CI on remote forks

.github/workflows/test-webapp-build.yaml

@@ -15,11 +15,16 @@ jobs:
     defaults:
       run:
         working-directory: ./web
-        
+
     name: Build webapp
     steps:
       - name: Checkout
         uses: actions/checkout@v3
+        with:
+          # Make sure the actual branch is checked out when running on pull requests
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          fetch-depth: 0
 
       - name: Install Dependencies
         run: npm install