Changed image to ubuntu-latest for app ci action

Author: raulbob

.github/workflows/sormas_app_ci.yml

@@ -26,7 +26,7 @@ on:
 jobs:
   test:
     name: android app test
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         # Even though we are using macos machines which should be faster thanks to hardware accelerations