Enable RSpec/AnyInstanceOf cop and move offenses to .rubocop_manual_todo.yml

What does this MR do?

This MR enables the 👮 RSpec/AnyInstanceOf (introduced via !19164 (merged) - but disabled) and moves current offenses into .rubocop_manual_todo.yml (see also !49416 (merged)) preventing new offenses sneaking into the codebase.

Usage (addition or change) of {expect,allow}_any_instance_of last month was 39 but should be 0.

$ git log -p --since="1 month ago" spec ee/spec | rg "^\+.\s+(expect|allow)_any_instance_of" | wc -l
39

Contributes to #34997 (closed).

Steps to generate the offenses

1. Enable 👮 in .rubocop.yml
2. Regenerate config via bundle exec rubocop --auto-gen-config --auto-gen-only-exclude --exclude-limit=10000 spec ee/spec
3. Have a shower or two 🚿 🚿
4. Move offenses from .rubocop_todo.yml to .rubocop_manual_todo.yml
5. Verify via bundle exec rubocop --only RSpec/AnyInstanceOf spec ee/spec

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team