Make Issue/PR/projects more compact, misc CSS tweaks (#24459)

- Remove various horizontal dividers on repo pages that didn't provide
visual benefit
- Remove label/milestone pills on single issue/pr page
- Remove issue-related pill buttons on projects page
- Increase contrast of color-secondary on arc-green
- Improve notifications icon, make circle bigger
- Remove some inline styles
- Fix focus in issue/pr title edit and select all text on button click

### Issue and PR before and after

<img width="1249" alt="Screenshot 2023-05-01 at 11 44 22"
src="https://user-images.githubusercontent.com/115237/235436662-a708288e-84fb-4b2e-a5a2-3a1c17d28f6c.png">
<img width="1248" alt="Screenshot 2023-05-01 at 11 58 51"
src="https://user-images.githubusercontent.com/115237/235437992-f863e483-f3cc-4cc1-8204-fd223647a0c9.png">



### Projects before and after

<img width="1255" alt="Screenshot 2023-05-01 at 11 41 02"
src="https://user-images.githubusercontent.com/115237/235436433-0deb85d6-4e7d-4e74-847f-254cc70a0cf9.png">
<img width="1267" alt="Screenshot 2023-05-01 at 11 40 03"
src="https://user-images.githubusercontent.com/115237/235436431-715b13cb-f78c-4d86-b27a-9229f9738c5b.png">


### Releases before and after

<img width="1243" alt="Screenshot 2023-05-01 at 11 41 12"
src="https://user-images.githubusercontent.com/115237/235436457-b655ee6f-03b8-4595-8d8c-b15ea469e988.png">
<img width="1240" alt="Screenshot 2023-05-01 at 11 40 10"
src="https://user-images.githubusercontent.com/115237/235436456-05a2a0dd-7cbb-4f26-b0d3-4f667df4bb95.png">

### Misc

<img width="58" alt="Screenshot 2023-05-01 at 10 49 13"
src="https://user-images.githubusercontent.com/115237/235432494-936ce995-6e22-47bc-ab2d-c9e93d31987d.png">
<img width="57" alt="Screenshot 2023-05-01 at 18 57 08"
src="https://user-images.githubusercontent.com/115237/235492430-1d32cfe0-0f2c-467c-b2fa-925b27e30e0e.png">


Issue title edit and wrap:

<img width="1238" alt="Screenshot 2023-05-01 at 12 34 40"
src="https://user-images.githubusercontent.com/115237/235441407-d5067a57-e586-4865-a652-282e5944abb4.png">
<img width="1232" alt="Screenshot 2023-05-01 at 12 06 24"
src="https://user-images.githubusercontent.com/115237/235438710-1a543dda-220f-4d87-8f93-f1710c0695f0.png">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/features/repo-legacy.js

@@ -469,11 +469,7 @@ export function initRepository() {
     return;
   }
 
-  // File list and commits
-  if ($('.repository.file.list').length > 0 || $('.branch-dropdown').length > 0 ||
-    $('.repository.commits').length > 0 || $('.repository.release').length > 0) {
-    initRepoBranchTagSelector('.js-branch-tag-selector');
-  }
+  initRepoBranchTagSelector('.js-branch-tag-selector');
 
   // Options
   if ($('.repository.settings.options').length > 0) {