Simplify quality-flutter matrix

Let's use the package name in the matrix and pre-append the path when
necessary.

.github/workflows/qa.yaml

@@ -91,7 +91,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu, windows]
-        package: ["gui/packages/p4w_ms_store", "gui/packages/ubuntupro"]
+        package: ["p4w_ms_store", "ubuntupro"]
     runs-on: ${{ matrix.os }}-latest
     steps:
       - name: Set up git
@@ -108,7 +108,7 @@ jobs:
         uses: actions/checkout@v4
       - name: Set up Go
         # We need to set up Go so that the agent can be built for the end-to-end tests
-        if: matrix.package == 'gui/packages/ubuntupro'
+        if: matrix.package == 'ubuntupro'
         uses: actions/setup-go@v4
         with:
           go-version-file: windows-agent/go.mod
@@ -121,13 +121,13 @@ jobs:
         uses: ./.github/actions/flutter-qa/
         with:
           flutter-version: ${{ steps.load.outputs.data.flutter-version }}
-          package-dir: '${{ matrix.package }}'
-          run-build-runner: ${{ contains(matrix.package, 'ubuntupro') }}
+          package-dir: gui/packages/${{ matrix.package }}
+          run-build-runner: ${{ matrix.package ==  'ubuntupro' }}
       - name: Ensure module files are up to date
         uses: canonical/desktop-engineering/gh-actions/common/has-diff@main
         with:
-          working-directory: ${{ matrix.package }}
-          paths-to-ignore: ${{ matrix.package == 'gui/packages/ubuntupro' && 'pubspec.lock' || '' }}
+          working-directory: gui/packages/${{ matrix.package }}
+          paths-to-ignore: ${{ matrix.package == 'ubuntupro' && 'pubspec.lock' || '' }}
           fail-on-diff: true
 
   flutter-integration: