Refactor some trivial problems (#34959)

1. make our "route group pattern match" also update chi's RoutePattern
2. fix incorrect "NotFound" call in conda package
3. make ".flex-item .flex-item-main" has a general gap, then no need to
use `tw` tricks
4. improve the "test webhook" UI

routers/api/packages/conda/conda.go

@@ -51,7 +51,7 @@ func ListOrGetPackages(ctx *context.Context) {
 		DownloadPackageFile(ctx)
 		return
 	}
-	ctx.NotFound(nil)
+	http.NotFound(ctx.Resp, ctx.Req)
 }
 
 func EnumeratePackages(ctx *context.Context) {