Remove all "floated" CSS styles (#32691)

flex but don't float

diff with ignoring spaces :
https://github.com/go-gitea/gitea/pull/32691/files?diff=split&w=1

related pages:

### admin users

![image](https://github.com/user-attachments/assets/40dd4c46-3f5b-4a68-89b0-d0a9a806f1fc)

### milestone

![image](https://github.com/user-attachments/assets/e3efb630-f07c-4c9d-b877-71e28cddcdce)

### user account setting

![image](https://github.com/user-attachments/assets/d15609ee-016d-4aee-999a-b5455fe6185c)

templates/repo/issue/milestone_new.tmpl

@@ -5,7 +5,7 @@
 		<div class="issue-navbar">
 			{{template "repo/issue/navbar" .}}
 			{{if and (or .CanWriteIssues .CanWritePulls) .PageIsEditMilestone}}
-				<div class="ui right floated secondary menu">
+				<div class="ui right">
 					<a class="ui primary button" href="{{$.RepoLink}}/milestones/new">{{ctx.Locale.Tr "repo.milestones.new"}}</a>
 				</div>
 			{{end}}