Resolve "Navigation - Move contextual navigation to sidebar"

Closes #34023

See merge request !12470

Backport inline prop on loading_icon from EE

See merge request !12490

Refactor emoji helpers in preparation for async loading

See merge request !12432

[ci skip]

Ignore JSON files generated from PO files

See merge request !12329

Fix head pipeline stored in merge request for external pipelines

Closes #34130

See merge request !12478

[ci skip]

Update mmap2 gem to fix missing symbol error that happens on some installations from source

Closes #34221

See merge request !12492

Make the SimpleExecutor rescue exceptions in the executing Checks

See merge request !12487

Update mmap2 gem tha disables mmap_obj.gsub! as current implementation uses method that is no longer part of Ruby API

See
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2246#note_33577729

ruby 2.4 compat: update to webmock 2.3.2

See merge request !12471

Update templates for 9.3

See merge request !12461

Update dependencies list for 9.3

See merge request !12462

Fix application error when Project#last_activity_at is nil

Closes #34276

See merge request !12443

Slightly refactor pipeline schedules form in preparation for additions

See merge request !12134

Refactor group members tests

See merge request !12465

Adjust commit partial cache key to fix browse buttons

Closes #26899

See merge request !12393

Merge branch '34014-submitting-reply-to-existing-diff-discussion-using-cmd-ctrl-enter-submits-twice-and-refreshes-page' into 'master'

Resolve "Submitting reply to existing diff discussion using Cmd/Ctrl+Enter submits twice and refreshes page"

Closes #34014

See merge request !12352

Resolve "Submitting reply to existing diff discussion using Cmd/Ctrl+Enter submits twice and refreshes page"

Clean up Gitlab::Git::Commit.find_all

See merge request !12476