"On" lightning rod bottom texture is still mapped incorrectly

Discovered while testing MC-262700.

The bug

The fix for MC-203605 only affected non-"powered" lightning rods. The bottom of powered lightning rods is still not mapped correctly.

Since the texture is completely white this requires a resource pack to see.

How to reproduce

1. Download and apply the attached resource pack
2. Look at the bottom of a powered lightning rod versus an unpowered lightning rod

Expected results

Mapping that makes sense.

Actual results

The bottom of powered lightning rods looks awful.