Merge https://github.com/google/adk-python/pull/2651
### Summary
Correct a misspelling in the build configuration:
- "swtich" → "switch" in `pyproject.toml`.
### Rationale
This is a spelling fix only. It improves readability and avoids potential confusion in configuration.
There is no impact on runtime behavior, tests, or public APIs.
### Notes
- Follows Conventional Commits style for build/config changes (`build:`).
- CLA status should be green via the Google CLA bot.
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/2651 from marsboy02:docs/fix-type-pyproject b78c014c864b1a143ffc157c7a8c807f5f19d31d
PiperOrigin-RevId: 828221776
