feat: Add items and title to ToolParameter/ToolParamDefinition (#3003)

# What does this PR do?
<!-- Provide a short summary of what this PR does and why. Link to
relevant issues if applicable. -->
Add items and title to ToolParameter/ToolParamDefinition. Adding items
will resolve the issue that occurs with Gemini LLM when an MCP tool has
array-type properties.

<!-- 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.* -->
Unite test cases will be added.

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Kai Wu <kaiwu@meta.com>
Co-authored-by: Ashwin Bharambe <ashwin.bharambe@gmail.com>

llama_stack/apis/tools/tools.py

@@ -27,6 +27,8 @@ class ToolParameter(BaseModel):
     :param parameter_type: Type of the parameter (e.g., string, integer)
     :param description: Human-readable description of what the parameter does
     :param required: Whether this parameter is required for tool invocation
+    :param items: Type of the elements when parameter_type is array
+    :param title: (Optional) Title of the parameter
     :param default: (Optional) Default value for the parameter if not provided
     """
 
@@ -34,6 +36,8 @@ class ToolParameter(BaseModel):
     parameter_type: str
     description: str
     required: bool = Field(default=True)
+    items: dict | None = None
+    title: str | None = None
     default: Any | None = None