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/tests/eval/test_eval.py

@@ -9,7 +9,6 @@ import pytest
 
 from llama_stack.apis.common.content_types import URL
 from llama_stack.apis.common.type_system import ChatCompletionInputType, StringType
-
 from llama_stack.apis.eval.eval import (
     AppEvalTaskConfig,
     BenchmarkEvalTaskConfig,
@@ -19,6 +18,7 @@ from llama_stack.apis.inference import SamplingParams
 from llama_stack.apis.scoring_functions import LLMAsJudgeScoringFnParams
 from llama_stack.distribution.datatypes import Api
 from llama_stack.providers.tests.datasetio.test_datasetio import register_dataset
+
 from .constants import JUDGE_PROMPT
 
 # How to run this test: