[Touchpad Setting] Hide Touchpad page when there's no connected one

The option for entering page already has complete check condition.
Update the same check logic to isSeachable in setting page to hide
page when there's no touchpad connected.
Also apply check on trackpadTouchGesture.

Test: verify on device
Bug: 346497646
Flag: EXEMPT bugfix
Change-Id: I1730c7bd1fd2615dc1725ec0cc32293254e5b54a