Revert dart:web to ^0.2.1-beta

packages/devtools_app/pubspec.yaml

diff --git a/packages/devtools_app/pubspec.yaml b/packages/devtools_app/pubspec.yaml
index 3e846a0..4c76ad2 100644
--- a/packages/devtools_app/pubspec.yaml
+++ b/packages/devtools_app/pubspec.yaml
@@ -67,7 +67,7 @@
   vm_service: ^11.10.0
   # TODO https://github.com/dart-lang/sdk/issues/52853 - unpin this version
   vm_snapshot_analysis: 0.7.2
-  web: 0.3.0
+  web: ^0.2.1-beta
   web_socket_channel: ^2.1.0
   # widget_icons: ^0.0.1