Removes spacing from system and discussion notes

app/assets/javascripts/diffs/components/diff_file_header.vue

...s/javascripts/notes/components/diff_discussion_header.vue

app/assets/javascripts/notes/components/discussion_notes.vue

app/assets/javascripts/notes/components/noteable_note.vue

app/assets/javascripts/notes/components/notes_app.vue

...ts/javascripts/notes/components/toggle_replies_widget.vue

...ascripts/vue_shared/components/notes/placeholder_note.vue

...s/javascripts/vue_shared/components/notes/system_note.vue

...vascripts/vue_shared/components/registry/history_item.vue

app/assets/stylesheets/framework/diffs.scss

app/assets/stylesheets/framework/timeline.scss

app/assets/stylesheets/page_bundles/merge_requests.scss

app/assets/stylesheets/pages/issuable.scss

app/assets/stylesheets/pages/notes.scss

app/views/shared/notes/_note.html.haml

...ets/stylesheets/components/batch_comments/draft_note.scss

...end/notes/components/__snapshots__/notes_app_spec.js.snap

.../frontend/notes/components/diff_discussion_header_spec.js

spec/frontend/notes/components/note_header_spec.js

spec/frontend/notes/components/noteable_note_spec.js