[Code health] Fixes and cleanup of `LocalMutationSyncWorker`

[gino-m]

Code health improvements which came up while fixing #2129:

Recommended:

• [ ] Warn and ignore mutations not belonging to current signed in user (#2237)
• [ ] Wrap remoteDataStore.applyMutations in MutationRepository
• [x] #2236

Nice to have:

• [ ] Log an error if "create" submissions were enqueued after "edit" submissions
• [ ] Replace MutationRepository.markAs.. methods with saveMutationsLocally and helper on Mutation
• [ ] Improve naming of finalizePendingMutationsForMediaUpload() and finalizeDeletions()
• [ ] Only call enqueueSyncWorker() if media uploads are pending for this LOI
• [ ] Extract business logic into UserDataUploadUseCase
• [ ] Move getPendingOrEligibleFailedMutations() into repository (#2237)

Not needed:

• ~Stop marking all mutations for an LOI as IN_PROGRESS at once. Instead, process each mutation individually, and set IN_PROGRESS before actually processing.~
  • We do this because we process mutations in batch.
• ~Abort updates to this LOI if any mutations were unsuccessful~
  • Mutations are applied as a batch write, which are atomic.

@scolsen Breaking these out so we can keep moving forward

[scolsen]

https://github.com/google/ground-android/pull/2237 will take care of:

Warn and ignore mutations not belonging to current signed in user Move getPendingOrEligibleFailedMutations() into repository