Don't delay child pressed state in freeform mode

DecorCaptionView is used in app view hierarchy in freeform mode
and it inherits default ViewGroup#shouldDelayChildPressedState
implementation, which returns true by default for compatibility
reasons.
This results in touch not delivered to child views in some cases
until there is movement or up action. E.g. touch on SeekBar will
not change the position of control instantly in freeform, while
it does in other modes.
This CL disables delaying child pressed state for DecorCaptionView.

Bug: 30037893
Change-Id: I4917143610b6c0d404d2395670de9525c10f2a6c