Add ability to `Add comment now` in middle of a review when editing a pending comment

From feedback issue

Issue

We removed the option to Add comment now on every single pending comment to reduce information overload. However, sometimes a user may add a comment to a review and then realize they want to "add comment now." At this time, you can no longer do that.

Proposal

Editing a comment

• Add option to Add comment now

Current	Proposed

Editing threaded comment (with resolve option)

• Remove Comment and resolve thread (I'm not sure it's working as intended anyway 🤔)
• Add Add comment now
• Include Resolve thread checkbox (which should retain previous selection; ie if user selected Resolve when making the original threaded comment, it should still be checked in edit mode)

Current	Proposed

Availability and Testing

• We currently have an end to end test for reviews with multiple comments qa/qa/specs/features/browser_ui/3_create/merge_request/suggestions/batch_suggestion_spec.rb. Recommendation is to modify this test or create a new test, which covers the functionality of being able to add a comment immediately while a review is ongoing.
• Replace test code (if any) associated with Comment and resolve thread button with check box select->Save comment button click.