Wrap tool invocation in Invoke-OAIFunctionCall with try/catch and ret…

[dfinke]

…urn informative error on failure

[Copilot]

Pull Request Overview

This PR adds error handling to the tool invocation process in Invoke-OAIFunctionCall. When a tool function throws an exception during execution, the error is now caught and returned as an informative message instead of propagating the exception.

Key Changes:

• Wrapped the tool function invocation in a try/catch block to handle execution errors gracefully
• Returns a descriptive error message containing the function name, arguments, and error details when invocation fails

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[Copilot]

The error message includes raw arguments from $toolCall.function.arguments which may not be helpful if the arguments were already parsed. Consider using $toolFunctionArgs | ConvertTo-Json -Compress instead to show the actual parsed arguments that were passed to the function.

Suggested change

	$result = "Error invoking function $($toolFunctionName) with arguments $($toolCall.function.arguments): $_"
	$result = "Error invoking function $($toolFunctionName) with arguments $($toolFunctionArgs | ConvertTo-Json -Compress): $_"