Don't animate Volume Panel initial state

When the Volume Panel opens all the sliders update simultaneously. This
puts a lot of pressure on Compose, specially given that the recent
updates made those animations more elaborate.

Flag: com.android.systemui.volume_redesign
Fixes: 403737312
Test: atest VolumePanelScreenshotTest
Test: manual on the foldable. Open and close volume panel with increased
animation scale

Change-Id: I82895614566d44b4479b708765e68edec6ea748e