litellm_fix(lint): remove unused ToolNameValidationResult imports

Fixes ruff F401 errors in check_code_and_doc_quality CI job.

**Regression introduced in:** 41ec820 (fix files) - added files with unused imports

## Problem
ToolNameValidationResult is imported but never used in:
- litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
- litellm/proxy/management_endpoints/mcp_management_endpoints.py

## Fix
```diff
-        ToolNameValidationResult,
```

Removed from both import statements.

## Changes
- mcp_server_manager.py: -1 line (removed unused import)
- mcp_management_endpoints.py: -1 line (removed unused import)

litellm/proxy/_experimental/mcp_server/mcp_server_manager.py

@@ -67,7 +67,6 @@ from litellm.types.utils import CallTypes
 try:
     from mcp.shared.tool_name_validation import (  # type: ignore
         SEP_986_URL,
-        ToolNameValidationResult,
         validate_tool_name,
     )
 except ImportError:

litellm/proxy/management_endpoints/mcp_management_endpoints.py

@@ -60,7 +60,6 @@ except ImportError as e:
 if MCP_AVAILABLE:
     try:
         from mcp.shared.tool_name_validation import (  # type: ignore
-            ToolNameValidationResult,
             validate_tool_name,
         )
     except ImportError: