feat: new cunstructor and conversion utilities for call tool operations

[hashemix]

📌 Summary

Added new utility functions for creating and converting types related to CallToolResult calls. These functions simplify the process of creating CallToolResult instances or returning errors when a CallToolRequest fails.

Usage example:

• Return a Unknown Tool Error

 async fn handle_call_tool_request(
        &self,
        request: CallToolRequest,
    ) -> Result<CallToolResult, CallToolError> {

       ////............

       return Err(CallToolError::unknown_tool(tool_name)),

}

• Return a CallToolResult with TextContent :

async fn handle_call_tool_request(
        &self,
        request: CallToolRequest,
    ) -> Result<CallToolResult, CallToolError> {

       ////............

       return Ok(CallToolResult::text_content(
                    format!( "Successfully created directory {}", path),
                    None,
                ));

}