feat: customized_tool_names param to VisionAgentCoder

[MingruiZhang]

Allow user to input customized_tool_names to VisionAgentCoder so user and limit and customize what tool to use.

The implementation is non-destructive, it only changes input of write_plans (so planner only uses provided customized_tool_names + a list of util tools (such as save_image). the rest is still up to VisionAgentCoder.

This means the tool user pick is not mandatory, VisionAgentCoder might still ignore the customized_tool_names if it doesn't think it solves the issue, even though it is the only choice it has

Test Case 1: default to all tools if customized_tool_names not provided

Test Case 2: only use tools from customized_tool_names if provided

Test Case 3: if provided tool name that does not exist yet, throw error

[dillonalaird]

Looks good! I'd just make that one change to the default argument and then merge