build: format codebase imports using ruff linter (#1028)

# What does this PR do?

- Configured ruff linter to automatically fix import sorting issues.
- Set --exit-non-zero-on-fix to ensure non-zero exit code when fixes are
applied.
- Enabled the 'I' selection to focus on import-related linting rules.
- Ran the linter, and formatted all codebase imports accordingly.
- Removed the black dep from the "dev" group since we use ruff

Signed-off-by: Sébastien Han <seb@redhat.com>

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
[Describe the tests you ran to verify your changes with result
summaries. *Provide clear instructions so the plan can be easily
re-executed.*]

[//]: # (## Documentation)
[//]: # (- [ ] Added a Changelog entry if the change is significant)

Signed-off-by: Sébastien Han <seb@redhat.com>

llama_stack/providers/inline/tool_runtime/code_interpreter/code_env_prefix.py

@@ -82,7 +82,11 @@ import sys as _sys
 # them with linters - they're used in code_execution.py
 from contextlib import (  # noqa
     contextmanager as _contextmanager,
+)
+from contextlib import (
     redirect_stderr as _redirect_stderr,
+)
+from contextlib import (
     redirect_stdout as _redirect_stdout,
 )
 from multiprocessing.connection import Connection as _Connection