Send a test email using the specified template.
Args: template_id: Template ID to use for test email. test_request: Test email request with recipient and variables. request: FastAPI request object for accessing app state.
Returns: Success message with email details.
Raises: HTTPException: 404 if template not found, 400 if no email provider configured, 500 if sending fails.
Successful Response
The response is of type Response Send Test Email Api V1 Admin Email Templates Template Id Test Post · object.