Updated bitrise.yml to fix failing test case due to glean sdk_generator (#8047)
Updated bitrise.yml to fix failing test case due to glean sdk_generator (#8047)

- We only move sdk_generator file from MozillaAppServices framework when publishing app and copy in all workflows for debug build.
- Also removed xcode12-release-and-beta workflow that wasn't used
Acidburn0zzz/firefox-ios,Acidburn0zzz/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,flodolo/firefox-ios,flodolo/firefox-ios,flodolo/firefox-ios,flodolo/firefox-ios,mozilla-mobile/firefox-ios,mozilla-mobile/firefox-ios,flodolo/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,flodolo/firefox-ios,flodolo/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,Acidburn0zzz/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios