Convert visibility to number (#29226) (#29244)

Backport #29226

Don't throw error while creating user (Fixes #29218)

---

The backport info from Giteabot
go-gitea/gitea#29226 (comment)
needs to specify the version, because the default is v1.18

(cherry picked from commit 39735c43a8b6f7db3b3e3531ca9115a60335d524)

templates/admin/user/new.tmpl

@@ -26,7 +26,7 @@
 				<div class="inline field {{if .Err_Visibility}}error{{end}}">
 					<span class="inline required field"><label for="visibility">{{ctx.Locale.Tr "settings.visibility"}}</label></span>
 					<div class="ui selection type dropdown">
-						<input type="hidden" id="visibility" name="visibility" value="{{if .visibility}}{{.visibility}}{{else}}{{printf "%d" .DefaultUserVisibilityMode}}{{end}}">
+						<input type="hidden" id="visibility" name="visibility" value="{{if .visibility}}{{printf "%d" .visibility}}{{else}}{{printf "%d" .DefaultUserVisibilityMode}}{{end}}">
 						<div class="text">
 							{{if .DefaultUserVisibilityMode.IsPublic}}{{ctx.Locale.Tr "settings.visibility.public"}}{{end}}
 							{{if .DefaultUserVisibilityMode.IsLimited}}{{ctx.Locale.Tr "settings.visibility.limited"}}{{end}}