E2E test: remove reload on diffs page

What does this MR do and why?

Essentially a revert of !115620 (merged) which was to workaround this bug which is now closed.

Resolves #412056

How to set up and validate locally

Run all tests (best to check pipeline) bundle exec rspec qa/specs/features/browser_ui/3_create/merge_request/suggestions/batch_suggestion_spec.rb is one test that uses this flow.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.