Fix failing pipeline on master

In !76030 (merged), I removed many of the RSpec/TimecopFreeze exclusions, however some of them are still needed causing a failing pipeline on master.

The MR was able to be merged because the rubocop job never ran. That is because the .gitlab/ci/rules.gitlab-ci.yml was not updated after !72791 (merged) moved .rubocop_manual_todo.yml into individual files.

This MR does two things:

1. Adds the missing offense exclusions back to .rubocop_todo/rspec/timecop_freeze.yml and
2. adds .rubocop_todo/**/* to the rules that trigger static analysis, so we can see whether the pipeline will pass before merging and avoid future problems like this.