Address some CodeQL security concerns (#35572)

Although there is no real security problem

routers/web/explore/repo.go

@@ -35,7 +35,7 @@ type RepoSearchOptions struct {
 // This function is also used to render the Admin Repository Management page.
 func RenderRepoSearch(ctx *context.Context, opts *RepoSearchOptions) {
 	// Sitemap index for sitemap paths
-	page := int(ctx.PathParamInt64("idx"))
+	page := ctx.PathParamInt("idx")
 	isSitemap := ctx.PathParam("idx") != ""
 	if page <= 1 {
 		page = ctx.FormInt("page")