Fix keyguard indication text on hub getting cut off with larger display/text sizes

The view-based keyguard indication text is placed via constraints to a
fixed distance from the bottom of the screen and is allowed to expand
as much as it wants. The compose-based one brings its own padding but
has its height limited to fit under the lock icon. Since the lock icon
UI element is much larger than the icon image itself, this leads to the
indication text being cut off.

This CL uses the correct bottom padding for the compose-based
indication area and removes its heigh restriction.

See bug for hierarchy snapshots.

Bug: 349510838
Fix: 349510838
Test: verified locally on device
Flag: com.android.systemui.communal_hub
Change-Id: I36a061c9dc585234ac62565ab63238106c4d2d54