Fix spacing in issue navbar (#30238)

Create a new `issue-navbar` class specifically for this bar, previous
class used in many places and I thought I had them all removed, but not
this one.

Fixes: https://github.com/go-gitea/gitea/issues/30226
(cherry picked from commit 944c76e78423405a33450eb3d07cd2b772f4a81c)

templates/repo/issue/choose.tmpl

@@ -3,7 +3,7 @@
 	{{template "repo/header" .}}
 	<div class="ui container">
 		{{template "base/alert" .}}
-		<div class="navbar">
+		<div class="issue-navbar">
 			{{template "repo/issue/navbar" .}}
 		</div>
 		<div class="divider"></div>

templates/repo/issue/labels.tmpl

@@ -2,7 +2,7 @@
 <div role="main" aria-label="{{.Title}}" class="page-content repository labels">
 	{{template "repo/header" .}}
 	<div class="ui container">
-		<div class="navbar tw-mb-4">
+		<div class="issue-navbar tw-mb-4">
 			{{template "repo/issue/navbar" .}}
 			{{if and (or .CanWriteIssues .CanWritePulls) (not .Repository.IsArchived)}}
 				<button class="ui small primary new-label button">{{ctx.Locale.Tr "repo.issues.new_label"}}</button>

templates/repo/issue/milestone_new.tmpl

@@ -2,7 +2,7 @@
 <div role="main" aria-label="{{.Title}}" class="page-content repository new milestone">
 	{{template "repo/header" .}}
 	<div class="ui container">
-		<div class="navbar">
+		<div class="issue-navbar">
 			{{template "repo/issue/navbar" .}}
 			{{if and (or .CanWriteIssues .CanWritePulls) .PageIsEditMilestone}}
 				<div class="ui right floated secondary menu">

web_src/css/modules/navbar.css

@@ -140,3 +140,8 @@
 .secondary-nav {
   background: var(--color-secondary-nav-bg) !important; /* important because of .ui.secondary.menu */
 }
+
+.issue-navbar {
+  display: flex;
+  justify-content: space-between;
+}