[graphite] Simplify Debug PaintKey logging

Bug: b/259548724
Change-Id: I457122a078959f90509d96233f6ec7f6b2763e8e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/855419
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
7 files changed