[marif-nexthop]

Pre-submission checklist

• I've ran the linters locally and fixed lint errors related to the files I modified in this PR. You can install the linters by running pip install -r requirements-dev.txt && pre-commit install
• pre-commit run

Summary

PR commit stack:

1. [Nexthop][m4340nhp] Add the platform_manager config #1871
2. This (top of stack)

Add the m4340nhp sensor_service.json and led_manager.json, and their ConfigLibTest checks.

Test Plan

The build-time config generator accepts both configs.

On a m4340nhp device, sensor_service_hw_tests and data_corral_service_tests pass.