Integrated error tracking setting API

What does this MR do?

Adds API support for integrated attribute (new column) in error tracking setting.

Integrated error tracking is a new feature that is in active development right now.

To use it you need 2 conditions to be true:

1. integrated_error_tracking feature flag
2. integrated attribute in error tracking setting

This merge request allows us to enable integrated error tracking for certain projects on GitLab.com without UI.

UI support for this setting is in draft !66845 (merged) and is planned for next release.

Issue #329596 (closed)

How to setup and validate locally (strongly suggested)

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.)