Harden bootstrap context registrations when apps are missing #27668
  Add this suggestion to a batch that can be applied as a single commit.
  This suggestion is invalid because no changes were made to the code.
  Suggestions cannot be applied while the pull request is closed.
  Suggestions cannot be applied while viewing a subset of changes.
  Only one suggestion per line can be applied in a batch.
  Add this suggestion to a batch that can be applied as a single commit.
  Applying suggestions on deleted lines is not supported.
  You must change the existing code in this line in order to create a valid suggestion.
  Outdated suggestions cannot be applied.
  This suggestion has been applied or marked resolved.
  Suggestions cannot be applied from pending reviews.
  Suggestions cannot be applied on multi-line comments.
  Suggestions cannot be applied while the pull request is queued to merge.
  Suggestion cannot be applied right now. Please check back later.
  
    
  
    
It's not expected that an app would be unavailable when the app
container is created but when services are registered, but Sentry tells
me on Nextcloud 21 there is an edge case where this can happen.
Therefore this patch hardens the code a bit to log a meaningful error
message and skipping the next code instead of logging a php notice for
the undefined index and an exception for calling a method on null.
Ref https://sentry.io/share/issue/4d592dbccd6a4d53bd0b402d9bbad8a6/ for the index notice
Ref https://sentry.io/share/issue/e51474a30afa475e8a4146f887ec7987/ for the method call on null
Those two issues popped up when I ran
occ app:enable sentry.