Remove obsolete comment from web_ui pubspec (#19100)

diff --git a/lib/web_ui/pubspec.yaml b/lib/web_ui/pubspec.yaml
index 5082fa6..a95a96b 100644
--- a/lib/web_ui/pubspec.yaml
+++ b/lib/web_ui/pubspec.yaml
@@ -8,7 +8,6 @@
   meta: ^1.1.8
 
 dev_dependencies:
-  # Pin the analyzer version as a temporary workaround for https://github.com/dart-lang/sdk/issues/42163
   analyzer: 0.39.10
   http: 0.12.1
   image: 2.1.13