improve Android language selection (#692)

restrict resource locales to "de" and "en" to properly to help Android respect language settings by user

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>
Co-authored-by: Jakob Möller <jakob.moeller@sap.com>

Corona-Warn-App/build.gradle

@@ -36,6 +36,8 @@ android {
         versionCode 31
         versionName "1.0.4"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        
+        resConfigs "de", "en"
 
         buildConfigField "String", "DOWNLOAD_CDN_URL", "\"$DOWNLOAD_CDN_URL\""
         buildConfigField "String", "SUBMISSION_CDN_URL", "\"$SUBMISSION_CDN_URL\""