Fix build and analysis failures (#6996)

- Update for a small breaking change in `package:jaspr_content` to `CustomComponent` as it was not meant to be implemented but rather extended.
- Ignore `experimental_member_use` in examples as in Dart 3.11 it's now reported as a warning.

Author: parlough

examples/language/analysis_options.yaml

@@ -0,0 +1,5 @@
+include: ../analysis_options.yaml
+
+analyzer:
+  errors:
+    experimental_member_use: ignore

site/lib/src/components/common/tabs.dart

@@ -8,11 +8,11 @@ import 'package:jaspr_content/jaspr_content.dart';
 import '../../util.dart';
 
 /// A tabs component where children tabs can be switched between by the user.
-class DashTabs implements CustomComponent {
+class DashTabs extends CustomComponent {
   static int _currentTabWrapperId = 0;
   static int _currentTabId = 0;
 
-  const DashTabs();
+  const DashTabs() : super.base();
 
   @override
   Component? create(Node node, NodesBuilder builder) {

site/pubspec.yaml

@@ -16,8 +16,8 @@ dependencies:
   http: ^1.4.0
   # Used for formatting dates in the SDK archive.
   intl: ^0.20.2
-  jaspr: ^0.21.5
-  jaspr_content: ^0.4.2
+  jaspr: ^0.21.6
+  jaspr_content: ^0.4.3
   # Used as our template engine.
   liquify: ^1.3.1
   markdown: ^7.3.0
@@ -38,8 +38,8 @@ dev_dependencies:
       ref: e2534e272132813a1cdcf6ea71a6fd9c904a69fb
   build_runner: ^2.8.0
   build_web_compilers: ^4.2.3
-  jaspr_builder: ^0.21.5
-  jaspr_test: ^0.21.5
+  jaspr_builder: ^0.21.6
+  jaspr_test: ^0.21.6
   lints: ^6.0.0
   sass: ^1.92.1
   sass_builder: ^2.3.1