[examples] Verdure client cleanup and dependency updates

[parlough]

No description provided.

[gemini-code-assist]

Code Review

This pull request focuses on cleaning up the Verdure client example and updating dependencies. The changes include adopting modern Dart features like pattern matching, using the spacing property in Row and Column widgets for cleaner layouts, and updating Riverpod and related packages to newer versions. The code is generally improved and more maintainable. I've left a couple of minor suggestions for improvement. Please also note that the repository's style guide requires a Pre-Review Checklist in the PR description, which is currently missing.

[gemini-code-assist]

Calling setState within a ref.listen callback inside the build method is discouraged as it can lead to unexpected rebuilds. Since _initialRequestSent is a flag to prevent re-execution and doesn't directly affect the UI, you can update it without setState to avoid an unnecessary widget rebuild. You can replace these lines with a simple assignment:

_initialRequestSent = true;