Set lower hotspotY for handwriting icon

On device with density forced to 1.6, hotspotY and bitmap height are
equal, which triggers the following exception:

java.lang.IllegalArgumentException: y hotspot lies outside of the bitmap area

Test: Boot up with display density 1.6, notice that PointerIcon
      exception is gone.
Fixes: https://gitlab.com/LineageOS/issues/android/-/issues/7368
Change-Id: Ifca973fe30f25c0bc8102562a2c84641fea62f3e