Don't trampoline twice when opening security or privacy

Settings already trampolines to a two-pane version of deeplink
activities, doing another trampoline will wind up creating a second task
covering up the first, with the wrong layout.

Bug: 253554698
Test: manually
Change-Id: Ib7ba5c95cac2f644ade37a41f321d11c8f1d1b89