Define new config for Health Connect default app.

By default this is set as Health Contoller apk com.android.healthconnect.controller
which will be used for Pixel devices

OEM can set value of config_defaultHealthConnectApp in the device
Overlay file to change it to OEM specific system health app.

BUG: 258760247
Test: Manual - Tested by manually giving permission to Health controller apk
and reading the config value

Change-Id: I4c2c0490c0b46532a11fe796de1363636ab370f1