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/utils/memory/vector_store.py

@@ -15,13 +15,14 @@ from urllib.parse import unquote
 import chardet
 import httpx
 import numpy as np
-
 from llama_models.llama3.api.tokenizer import Tokenizer
+from numpy.typing import NDArray
+from pypdf import PdfReader
 
 from llama_stack.apis.common.content_types import (
+    URL,
     InterleavedContent,
     TextContentItem,
-    URL,
 )
 from llama_stack.apis.tools import RAGDocument
 from llama_stack.apis.vector_dbs import VectorDB
@@ -30,9 +31,6 @@ from llama_stack.providers.datatypes import Api
 from llama_stack.providers.utils.inference.prompt_adapter import (
     interleaved_content_as_str,
 )
-from numpy.typing import NDArray
-
-from pypdf import PdfReader
 
 log = logging.getLogger(__name__)