Add inline script execution support to bundle run

[shreyas-goenka]

Changes

This PR adds the ability to execute scripts inline using the databricks bundle run command. This allows users to execute commands with the same authentication credentials as the bundle is configured to use..

Note: The auth credentials are passed to child processes via environment variables.

Why

Configuring downstream tools like DBConnect to use the same authentication credentials as your bundle can be challenging. Having this command allows users to directly run databricks bundle run -t foo -- uv run pytest (or equivalent) to directly run integration tests against the configured target without having to worry about how to pass authentication credentials to DBConnect.

Tests

Acceptance tests.

[denik]

Great work, thanks for working with the feedback.