Fix issue with PIN output content not center aligned as expected.

Before this all the dots were left aligned.

Fixes: 365648186
Test: turn on flexiglass
 1. Set PIN bouncer
 2. Enter pin digits and see the dots are horizontally centered
 3. disable flexiglass and enable compose_bouncer and verify the same
Flag: com.android.systemui.scene_container
Flag: com.android.systemui.compose_bouncer
Change-Id: Ib9cde15b0f2d3adc670360029648c6b6bcd1ff8b