thermal: seperate thermal config for charging

- Separate thermal config for charger mode and remove the unused thermal
throttling.
- Move charger pixel-thermal-symlink from common to project folder
to prevent the GKI version dependencies from blocking init.

Bug: 240897207
Test: usbc overheating protection and charging throttling worked
properly in charger.

Change-Id: I0ba3dabcc8c0c74e7e9334bc04a6fac875ac6b6c