Fix incorrect color of selected assignees when create issue (#26324) (#26372)

Backport #26324 by @yp05327

Before:

![image](https://github.com/go-gitea/gitea/assets/18380374/75d610b2-3823-4366-be85-c77c9106feff)

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/15afc6ac-f5ad-4e24-8983-fea8ace5921f)

Co-authored-by: yp05327 <576951401@qq.com>

Author: GiteaBot

templates/repo/issue/new_form.tmpl

@@ -170,11 +170,13 @@
 				<span class="no-select item {{if .HasSelectedLabel}}gt-hidden{{end}}">
 					{{.locale.Tr "repo.issues.new.no_assignees"}}
 				</span>
+				<div class="selected">
 				{{range .Assignees}}
 					<a class="item gt-p-2 muted gt-hidden" id="assignee_{{.ID}}" href="{{$.RepoLink}}/issues?assignee={{.ID}}">
 						{{avatar $.Context . 28 "gt-mr-3 gt-vm"}}{{.GetDisplayName}}
 					</a>
 				{{end}}
+				</div>
 			</div>
 		{{if and .PageIsComparePull (not (eq .HeadRepo.FullName .BaseCompareRepo.FullName)) .CanWriteToHeadRepo}}
 			<div class="ui divider"></div>