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/templates/template.py

@@ -9,6 +9,7 @@ from typing import Dict, List, Literal, Optional, Tuple
 
 import jinja2
 import yaml
+from pydantic import BaseModel, Field
 
 from llama_stack.apis.models.models import ModelType
 from llama_stack.distribution.datatypes import (
@@ -24,7 +25,6 @@ from llama_stack.distribution.datatypes import (
 from llama_stack.distribution.distribution import get_provider_registry
 from llama_stack.distribution.utils.dynamic import instantiate_class_type
 from llama_stack.providers.utils.kvstore.config import SqliteKVStoreConfig
-from pydantic import BaseModel, Field
 
 
 class RunConfigSettings(BaseModel):