Promote "history sharing on invite" out of developer options (#5480)

* Enable key-share-on-invite irrespective of feature flag

* Remove feature-flag dep: warning on starting chat with new people

* Remove feature-flag dep: invite from room member details

* Remove feature-flag dep: warning on new users in invite screen

* Remove feature-flag dep: from room details screen

* Remove feature-flag dep: starting chat from user profile screen

* Remove feature-flag dep: timeline info on forwarded keys

* Remove feature-flag dep: RoomScreenModel

* Remove `enableKeyShareOnInvite` from AppSettings

* Remove `enableKeyShareOnInvite` feature flag

* Remove outdated comments

* Update preview test room snapshots as their header now includes the history sharing icon

UnitTests/Sources/UserProfileScreenViewModelTests.swift

@@ -57,8 +57,6 @@ struct UserProfileScreenViewModelTests {
     
     @Test
     func startingDmWithUnknownUserFetchesIdentity() async throws {
-        ServiceLocator.shared.settings.enableKeyShareOnInvite = true
-        
         let profile = UserProfileProxy.mockAlice
         
         let clientProxy = ClientProxyMock(.init())