Implement action to setup Android emulator in CI

.github/workflows/ci.yml

@@ -281,12 +281,22 @@ jobs:
         python -m pip install -U pip
         python -m pip install git+https://github.com/beeware/briefcase.git
 
+    - name: Setup Android Emulator
+      id: emulator
+      if: matrix.backend == 'android'
+      uses: rmartin16/.github-beeware/.github/actions/setup-android@setup-android
+      with:
+        emulator-config: '{"avd":"beePhone","skin":"pixel_3a"}'
+
     - name: Test App
       working-directory: testbed
       timeout-minutes: 15
-      run: |
-        ${{ matrix.briefcase-run-prefix }} \
-          briefcase run ${{ matrix.platform }} --test ${{ matrix.briefcase-run-args }}
+      run: >
+        ${{ matrix.briefcase-run-prefix }}
+        briefcase run ${{ matrix.platform }}
+        --test
+        ${{ matrix.briefcase-run-args }}
+        ${{ steps.emulator.outputs.briefcase-run-args }}
 
     - name: Upload Logs
       uses: actions/[email protected]

changes/2597.misc.rst

@@ -0,0 +1 @@
+CI now uses a centralized action to configure the environment for using the Android emulator.