Only update udfps view params if addViewRunnable IS null

When addViewRunnable is null, this means there's no pending view.
Previously we were checking for the exact opposite by mistake.

Fixes: 333180884
Flag: ACONFIG com.android.systemui.udfps_view_performance NEXTFOOD
Flag: ACONFIG com.android.systemui.device_entry_udfps_refactor TRUNKFOOD
Test: atest UdfpsControllerOverlayTest
Change-Id: I2441e5840878c852f7519fc47bd620f692e4aa93