Commenting on a diff failing
https://sentry.gitlab.net/gitlab/gitlabcom/issues/3190511/?referrer=gitlab_plugin
```
DiffNote::NoteDiffFileCreationError: Failed to find diff line for: lib/gitlab/json_cache.rb, old_line: , new_line: 28
app/models/diff_note.rb:46:in `create_diff_file'
raise NoteDiffFileCreationError, DIFF_LINE_NOT_FOUND_MESSAGE % {
config/initializers/forbid_sidekiq_in_transactions.rb:58:in `block in committed!'
Sidekiq::Worker.skipping_transaction_check { super }
config/initializers/forbid_sidekiq_in_transactions.rb:10:in `skipping_transaction_check'
yield
config/initializers/forbid_sidekiq_in_transactions.rb:58:in `committed!'
Sidekiq::Worker.skipping_transaction_check { super }
lib/gitlab/database/load_balancing/connection_proxy.rb:126:in `block in write_using_load_balancer'
connection.send(...)
...
(183 additional frame(s) were not displayed)
```
issue