Fix incorrect visibility dropdown list in add/edit user page (go-gitea#23804)

Visibility dropdown list will not work in add/edit user page when error
occurred

Author: yp05327

routers/web/admin/users.go

@@ -105,6 +105,7 @@ func NewUserPost(ctx *context.Context) {
 	ctx.Data["PageIsAdmin"] = true
 	ctx.Data["PageIsAdminUsers"] = true
 	ctx.Data["DefaultUserVisibilityMode"] = setting.Service.DefaultUserVisibilityMode
+	ctx.Data["AllowedUserVisibilityModes"] = setting.Service.AllowedUserVisibilityModesSlice.ToVisibleTypeSlice()
 
 	sources, err := auth.Sources()
 	if err != nil {
@@ -273,6 +274,7 @@ func EditUserPost(ctx *context.Context) {
 	ctx.Data["PageIsAdmin"] = true
 	ctx.Data["PageIsAdminUsers"] = true
 	ctx.Data["DisableMigrations"] = setting.Repository.DisableMigrations
+	ctx.Data["AllowedUserVisibilityModes"] = setting.Service.AllowedUserVisibilityModesSlice.ToVisibleTypeSlice()
 
 	u := prepareUserInfo(ctx)
 	if ctx.Written() {