Replace spacing hack w/ pnum

This change also adds a correction for right-aligned glyph positions
within TextInterpolator by accounting for the offset value generated
by TextShaper.shapeText. The result is RTL positioning is capable of
reacting to changes in the view bounds because it is drawing relative
to the right side of the view, instead of the right side of the text
layout.

Bug: 414880000
Test: Checked visuals of new font
Flag: com.android.systemui.shared.clock_reactive_variants
Change-Id: I151eb4795b741840247a975c59b9fa228bf87604