fix(web): normalize content for edit history diff and fix comment history dropdown (#39616) (#39627)

Backport #39616 by @SergioBenitez

Editing a comment as follows:

```diff
# Deployment checklist

- Timeout: 30 seconds.
+ Timeout: 60 seconds.
Restart the worker before deploying.
Check the logs after deployment.
```

Gitea would render the history this way, before, inserting spurious new
lines:

<img width="1280" height="720" alt="before"
src="https://github.com/user-attachments/assets/5391167b-ac04-4746-b544-add926230ad8"
/>

With this change, it now renders it like this:

<img width="1280" height="720" alt="after"
src="https://github.com/user-attachments/assets/369f1f19-0eaf-4da5-99e5-aeedbac6050c"
/>

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Sergio Benitez <SergioBenitez@users.noreply.github.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/fomantic/build/components/dropdown.js

@@ -521,10 +521,14 @@ $.fn.dropdown = function(parameters) {
             : function(){}
           ;
           const dataKeyRemoteQueried = 'remote-queried';
-          if(module.is.remote() && !$module.data(dataKeyRemoteQueried)) {
+          // if the dropdown uses remote API, then it needs to query if:
+          // * its content is empty (can not show: no menu item)
+          // * it has not queried before (it has content, but we still need to query the remote API, e.g.: issue author list)
+          if(module.is.remote() && (!module.can.show() || !$module.data(dataKeyRemoteQueried))) {
             module.debug('No API results retrieved, searching before show');
             $module.data(dataKeyRemoteQueried, true)
             module.queryRemote(module.get.query(), module.show);
+            // can continue to "show" if there are menu items to avoid the lag of waiting for the remote API response
           }
           if( module.can.show() && !module.is.active() ) {
             module.debug('Showing dropdown');