Improve PR Review Box UI (#22986)

This PR follows: 
* #22950

### Before

The Review Box has many problems:

* It doesn't work for small screens.
* It has an anonying animation which makes the UI laggy.
* It uses "custom dropdown menu" which is very difficult to fine tune.
* `$().toggle('visible')` is not a correct call 
* jQuery just accepts any invalid `duration` argument:
`$().toggle('anyting')`
* The button is not a button.

<details>

![image](https://user-images.githubusercontent.com/2114189/219948865-6da3f39c-6fde-4c86-9e42-da5020f3d0c3.png)

</details>

### After

These problems are fixed, and eliminate many `!important` games.

<details>

![image](https://user-images.githubusercontent.com/2114189/219952744-8862fe1a-7ef1-49e4-bf92-2d0c1f104ee4.png)

![image](https://user-images.githubusercontent.com/2114189/219952771-be169a76-45fd-47a8-8f9c-b447d064f4ca.png)

![image](https://user-images.githubusercontent.com/2114189/219952784-3f52e9b7-64ce-4ad1-9553-64c33fb83042.png)

</details>

And most dropdown icons still looks good:

<details>

![image](https://user-images.githubusercontent.com/2114189/219952942-52866a00-e0f9-4af7-8fb5-eb1a8cad1ff3.png)

![image](https://user-images.githubusercontent.com/2114189/219948909-b3bfb844-f84e-4b79-ab1f-382ec66dec31.png)

</details>

Co-authored-by: delvh <leon@kske.dev>

web_src/less/_base.less

@@ -2476,24 +2476,13 @@ table th[data-sortt-desc] {
   }
 }
 
-/* fix up SVG dropdown triangles because fomantic thinks they are icon fonts */
-/* see https://github.com/go-gitea/gitea/issues/14014 */
-.ui.dropdown > .dropdown.icon,
-.btn-review > .dropdown.icon {
-  height: auto !important;
-  margin-left: .5rem !important;
-  margin-top: -1px !important;
-  margin-bottom: -1px !important;
-  margin-right: -.5rem !important;
+.ui.dropdown .svg.dropdown.icon,
+.svg.dropdown.icon {
+  margin-top: 0 !important; // reset the "ui.selection.dropdown > .dropdown.icon {margin-top}", for the Issue Dependencies dropdown
+  margin-right: -.5rem !important; // fix up SVG dropdown triangles because Fomantic thinks they are icon fonts
+  height: auto; // reset the ".ui.dropdown > .dropdown.icon {height}", otherwise the icon would be too small
 }
-.ui.button.dropdown > .dropdown.icon,
-.btn-review > .dropdown.icon {
-  float: right !important;
 
-  @media (max-width: 480px) {
-    display: none;
-  }
-}
 .ui.selection.dropdown > .search.icon,
 .ui.selection.dropdown > .delete.icon,
 .ui.selection.dropdown > .dropdown.icon {

web_src/less/_editor.less

@@ -13,7 +13,7 @@
 }
 
 .editor-toolbar {
-  opacity: 1 !important;
+  max-width: calc(100vw - 80px);
   border-color: var(--color-secondary);
 }
 

web_src/less/_repository.less

@@ -2864,11 +2864,6 @@
   margin-top: 10px;
 }
 
-.repo-button-row .dropdown > .dropdown.icon {
-  margin-left: .25rem !important;
-  margin-right: 0 !important;
-}
-
 .wiki .repo-button-row {
   margin-bottom: 0;
 }

web_src/less/_review.less

@@ -220,47 +220,45 @@ a.blob-excerpt:hover {
 
 // See the comment of createCommentEasyMDE() for the review editor
 // EasyMDE's options can not handle minHeight & maxHeight together correctly, we have to set minHeight in JS code
-#review-box .CodeMirror-scroll {
+.review-box-panel .CodeMirror-scroll {
   min-height: 80px;
   max-height: calc(100vh - 360px);
 }
 
 @media @mediaSm {
-  #review-box > .menu {
-    > .ui.segment {
-      width: 94vw;
-    }
-
-    .editor-toolbar {
-      overflow-x: auto;
-    }
-  }
-
-  #review-box .CodeMirror-scroll {
+  .review-box-panel .CodeMirror-scroll {
     max-width: calc(100vw - 70px);
   }
 }
 
 @media @mediaMd {
-  #review-box .CodeMirror-scroll {
+  .review-box-panel .CodeMirror-scroll {
     max-width: 700px;
   }
 }
 
 @media @mediaLg {
-  #review-box .CodeMirror-scroll {
+  .review-box-panel .CodeMirror-scroll {
     max-width: 800px;
   }
 }
 
 @media @mediaXl {
-  #review-box .CodeMirror-scroll {
+  .review-box-panel .CodeMirror-scroll {
     max-width: 900px;
   }
 }
 
-.review-box > .segment {
-  border: none !important;
+#review-box {
+  position: relative;
+}
+
+.review-box-panel {
+  position: absolute;
+  min-width: max-content;
+  top: 45px;
+  right: -5px;
+  z-index: 2;
 }
 
 #review-box .review-comments-counter {