Fix incorrect tailwind migration (#30007)

Fixes https://github.com/go-gitea/gitea/issues/30005. Regression from
https://github.com/go-gitea/gitea/pull/29945.

There was only once instance of `tw-content-center` before that PR, so I
just ran below command and reverted that one instance.

```sh
perl -p -i -e 's#tw-content-center#tw-items-center#g' web_src/js/**/* templates/**/* models/**/* tests/**/*
```

templates/projects/view.tmpl

@@ -1,7 +1,7 @@
 {{$canWriteProject := and .CanWriteProjects (or (not .Repository) (not .Repository.IsArchived))}}
 
 <div class="ui container">
-	<div class="tw-flex tw-justify-between tw-content-center gt-mb-4">
+	<div class="tw-flex tw-justify-between tw-items-center gt-mb-4">
 		<h2 class="gt-mb-0">{{.Project.Title}}</h2>
 		{{if $canWriteProject}}
 			<div class="ui compact mini menu">