Improve and fix bugs surrounding reactions (#24760)

- Slightly decrease size of reaction buttons
- Remove tooltip inside menu, it's obvious by the picture alone
- Fix top menu triangle
- Use `display: grid` to align icons in menu
- Use regular tooltip for reaction users
- Fix bug that deleted the reaction bar on clicking already reacted
reaction in dropdown

<img width="490" alt="Screenshot 2023-05-17 at 00 03 42"
src="61588b37-facb-4829-b75b-e1cb5dda8ca4">

<img width="67" alt="Screenshot 2023-05-17 at 00 11 14"
src="29605589-3b5f-40c6-8ad4-09923094bb8e">

<img width="211" alt="Screenshot 2023-05-17 at 00 29 30"
src="7d2725da-6a3d-4e42-a351-53647f79f762">
<img width="210" alt="Screenshot 2023-05-17 at 00 29 54"
src="b50f8364-033c-4445-ba25-61a814bb2d92">


<img width="892" alt="Screenshot 2023-05-17 at 00 12 20"
src="30a46424-406a-46e5-b4de-47172eb8679d">

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

web_src/css/themes/theme-arc-green.css

@@ -152,8 +152,8 @@
   --color-light: #00000028;
   --color-light-mimic-enabled: rgba(0, 0, 0, calc(40 / 255 * 222 / 255 / var(--opacity-disabled)));
   --color-light-border: #ffffff28;
-  --color-hover: #ffffff10;
-  --color-active: #ffffff16;
+  --color-hover: #ffffff19;
+  --color-active: #ffffff24;
   --color-menu: #2e323e;
   --color-card: #2e323e;
   --color-markup-table-row: #ffffff06;
@@ -170,7 +170,8 @@
   --color-project-board-bg: var(--color-secondary-light-2);
   --color-caret: var(--color-text); /* should ideally be --color-text-dark, see #15651 */
   --color-reaction-bg: #ffffff12;
-  --color-reaction-active-bg: var(--color-primary-alpha-40);
+  --color-reaction-hover-bg: var(--color-primary-light-4);
+  --color-reaction-active-bg: var(--color-primary-light-5);
   --color-tooltip-text: #ffffff;
   --color-tooltip-bg: #000000f0;
   --color-header-bar: #2e323e;