Update PiP dismiss target on theme change

Re-initiate the DismissCircleView upon theme change to make sure the PiP
dismiss target inherits the right theme color.

Bug: 199359063
Video: http://recall/-/aaaaaabFQoRHlzixHdtY/bIMe3fAFoW6Nw47Ye894MZ
Test: manually, see video
Change-Id: Ia65c633fd636114ddbdc2ff497245e2cb73f7745