Make Finamp use flutterw, update for 0.6.11

I've changed the build process for new versions to use flutterw as recommended in !12095 (closed)

Required

• The app complies with the inclusion criteria
• All related fdroiddata and RFP issues have been referenced in this merge request
• Builds with fdroid build

Strongly Recommended

• The upstream app source code repo contains the app metadata (summary/description/images/changelog/etc) in a Fastlane or Triple-T folder structure
• Releases are tagged

Suggested

• External repos are added as git submodules instead of srclibs
• Multiple apks for native code <!--If your app has native code and the size is large, please consider building multiple apks instead of one universal apk.--