during prekey rotation on keyserver, check if we have an unpublished prekey, and if we do, upload and mark them as published, then return

this matches the rotation logic on native

Depends on D12441

Resolves https://linear.app/comm/issue/ENG-6490/resolve-discrepancy-between-prekey-rotation-logics-on-native-and-the

called generate_prekey() to generate new content and notif prekeys. confirmed that the if condition was satisfied and the newly generated prekeys were uploaded to identity and marked as published