Fix broken resource definition.

notification_right_icon_size_low_ram appears to have been
circularly defined. This reverts the change made to this
field in ag/3938119.

Since the original CL reduced dp value of icon sizes, this
fix also does a best effort/proportional change to the
dp value of the icon, to 38dp (from 40dp).

Test: Build and install on sawfish, crash no longer repros.
Bug: 78598699
Change-Id: I73309fb39cc7cbc286e5a0cec69900590d3f0f54