Simplify samples index and remove cookbook recipes (#2102)

Remove the cookbook recipes from the samples index in a step to
eventually remove it as a whole.

The cookbook recipe listings in the index haven't been updated in a long
time, the support for updating them doesn't work, and this isn't
generally how people are finding cookbook recipes.

This has the added benefit of reducing repo size quite a bit due to the
large images.

web/samples_index/pubspec.yaml

@@ -1,30 +1,29 @@
 name: samples_index
-description: A visual index of Flutter samples
+description: A visual index of Flutter samples.
 homepage: https://github.com/flutter/samples/tree/main/web/samples_index
 version: 0.0.1
+publish_to: none
 
 environment:
   sdk: ^3.2.0
 
 dependencies:
-  json_annotation: ^4.8.1
-  path: ^1.8.3
-  yaml: ^3.1.2
-  mdc_web: ^0.6.0
-  sass_builder: ^2.2.1
   checked_yaml: ^2.0.3
-  webdriver: ^3.0.2
-  html: ^0.15.3
+  json_annotation: ^4.8.1
+  mdc_web: ^0.6.0
+  path: ^1.8.3
+  sass_builder: ^2.2.1
+  yaml: ^3.1.2
 
 dev_dependencies:
-  grinder: ^0.9.4
-  flutter_lints: ">=2.0.1 <4.0.0"
-  test: ^1.24.2
-  json_serializable: ^6.6.2
   build: ^2.4.0
   build_runner: ^2.4.2
   build_web_compilers: ^4.0.3
-  image: ">=3.2.0 <5.0.0"
+  grinder: ^0.9.4
+  image: ^4.1.3
+  json_serializable: ^6.6.2
+  lints: ^3.0.0
+  test: ^1.24.2
 
 # package:mdc_web needs to upgrade the version of material-components-web 12.0.0
 # or above, which includes this fix for the division operator: