Add sudo examples for inspecting inner call results

[Devpen787]

Summary

• make the sudo integration tests inspect the inner Sudid result instead of only checking outer extrinsic success
• add a failing wrapped-call example that shows why Sudid must be decoded
• add successful sudo and sudo_unchecked_weight examples using a root-only balances call

Why

Issue #1854 asks for an example of how to get the result of a wrapped sudo call. The existing tests only proved that the outer sudo extrinsic finalized, which can hide inner-call failure. This patch turns the sudo tests into concrete examples of reading sudo_result from the Sudid event.

Notes

• I could not run the full integration test suite locally because testing/test-runtime requires a local substrate or substrate-node binary on PATH.
• cargo fmt --all was run.

Closes #1854