Use the format_response hook when recording performance bar metrics for API requests

What does this MR do?

With endpoint_run, we were missing some Redis / DB calls that are triggered during the serialization of data.

This happens very frequently because ActiveRecord relations are loaded lazily and these are most likely going to be triggered during serialization.

How to setup and validate locally (strongly suggested)

1. Add localhost:3000/api/v4/projects to the performance bar
2. Check api_json.log and compare the db_count and redis_calls to the numbers in the performance bar.

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.