not show link to migration on repo reate page when it was disabled (#15957)

* not show link to migration on repo reate page when it was disabled

Signed-off-by: a1012112796 <1012112796@qq.com>

* fix lint

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/repo/create.tmpl

@@ -10,7 +10,9 @@
 				<div class="ui attached segment">
 					{{template "base/alert" .}}
 
+					{{if not $.DisableMigrations}}
 						<p class="ui center">{{.i18n.Tr "repo.new_repo_helper" (printf "%s%s" AppSubUrl "/repo/migrate") | Safe}}</p>
+					{{end}}
 
 					{{if not .CanCreateRepo}}
 						<div class="ui negative message">