Notif redesign: Account for low ram icon size

These sizes are technically the same by default, but we should still
respect the contract of the declared dimensions.

Bug: 371174789
Test: cannot test, will be unit tested in follow-up
Flag: android.app.notifications_redesign_app_icons
Change-Id: Ic23f2c4132ef25585a8546ed02901820fdf2ca6d