MH2 | Implement dynamic sensors callbacks on HalProxy

Additionally, have HalProxyCallback::processEvents use
HalProxy::setSubHalIndex static method instead of its own helper.
Add unit tests to test the dynamic sensor methods.

Bug: 136511617
Test: New unit tests are passing.
Change-Id: Ib903291a83df2fafa480082f9305c594bd325f79
5 files changed