Update DevTools rev to 21132242f6e12b26e3d9c0f06109361f7e519608

Note: `Handler` was removed from `devtools_server` in flutter/devtools#9170

Change-Id: Ic29658a1caece780a72125ca8ed040bbdc2405e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/426540
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Elliott Brooks <[email protected]>
Reviewed-by: Kenzie Davisson <[email protected]>

Author: elliette

DEPS

@@ -101,7 +101,7 @@ vars = {
   "boringssl_rev": "a70ec8dd2cc1816e9deadda2f6e536640380e20c",
   "browser-compat-data_tag": "ac8cae697014da1ff7124fba33b0b4245cc6cd1b", # v1.0.22
   "cpu_features_rev": "936b9ab5515dead115606559502e3864958f7f6e",
-  "devtools_rev": "4b7eda127290518ad9e0dea4dcb9510b6e5e4a41",
+  "devtools_rev": "21132242f6e12b26e3d9c0f06109361f7e519608",
   "icu_rev": "43953f57b037778a1b8005564afabe214834f7bd",
   "jinja2_rev": "2222b31554f03e62600cd7e383376a7c187967a1",
   "libcxx_rev": "bd557f6f764d1e40b62528a13b124ce740624f8f",

pkg/dds/lib/src/devtools/handler.dart

@@ -10,7 +10,7 @@ import 'dart:typed_data';
 import 'package:devtools_shared/devtools_deeplink_io.dart';
 import 'package:devtools_shared/devtools_extensions.dart';
 import 'package:devtools_shared/devtools_extensions_io.dart';
-import 'package:devtools_shared/devtools_server.dart' hide Handler;
+import 'package:devtools_shared/devtools_server.dart';
 import 'package:devtools_shared/devtools_shared.dart';
 import 'package:mime/mime.dart';
 import 'package:path/path.dart' as path;