health: skip VTS on healthd if vendor HAL is present.

If vendor HAL is present, healthd is not used by the framework. VTS should
skip testing it when this is the case.

Provide a --force option to the test if one wants to test healthd.

Fixes: 118852225
Test: on walleye, test healthd with and without --force.

Change-Id: I85f792f25406b1c02887a0ac273730e719003e2f