Don't display creating page button in a mirror wiki repository (#24395)

A mirror repository with wiki is also a mirror. So creating page from UI
should be disabled. This PR hides the button like other places.

options/locale/locale_en-US.ini

@@ -1904,6 +1904,7 @@ settings.sync_mirror = Synchronize Now
 settings.mirror_sync_in_progress = Mirror synchronization is in progress. Check back in a minute.
 settings.site = Website
 settings.update_settings = Update Settings
+settings.update_mirror_settings = Update Mirror Settings
 settings.branches.switch_default_branch = Switch Default Branch
 settings.branches.update_default_branch = Update Default Branch
 settings.branches.add_new_rule = Add New Rule

templates/repo/settings/options.tmpl

@@ -153,7 +153,7 @@
 									</div>
 									{{end}}
 									<div class="field">
-										<button class="ui green button">{{$.locale.Tr "repo.settings.update_settings"}}</button>
+										<button class="ui green button">{{$.locale.Tr "repo.settings.update_mirror_settings"}}</button>
 									</div>
 								</form>
 							</td>

templates/repo/wiki/pages.tmpl

@@ -5,7 +5,7 @@
 		<h2 class="ui header gt-df gt-ac gt-sb">
 			<span>{{.locale.Tr "repo.wiki.pages"}}</span>
 			<span>
-				{{if and .CanWriteWiki (not .IsRepositoryMirror)}}
+				{{if and .CanWriteWiki (not .Repository.IsMirror)}}
 					<a class="ui green small button" href="{{.RepoLink}}/wiki?action=_new">{{.locale.Tr "repo.wiki.new_page_button"}}</a>
 				{{end}}
 			</span>