Refactor admin user filter query parameters (#18965)

Only pass `status_filter` on admin page
Use a more general method to pass query parameters, remove hard-coded keys

routers/web/explore/user.go

@@ -82,7 +82,9 @@ func RenderUserSearch(ctx *context.Context, opts *user_model.SearchUserOptions,
 
 	pager := context.NewPagination(int(count), opts.PageSize, opts.Page, 5)
 	pager.SetDefaultParams(ctx)
-	pager.SetUserFilterParams(ctx)
+	for paramKey, paramVal := range opts.ExtraParamStrings {
+		pager.AddParamString(paramKey, paramVal)
+	}
 	ctx.Data["Page"] = pager
 
 	ctx.HTML(http.StatusOK, tplName)