[SPARK-3858][SQL] Pass the generator alias into logical plan node

The alias parameter is being ignored, which makes it more difficult to specify a qualifier for Generator expressions.

Author: Nathan Howell <nhowell@godaddy.com>

Closes #2721 from NathanHowell/SPARK-3858 and squashes the following commits:

8aa0f43 [Nathan Howell] [SPARK-3858][SQL] Pass the generator alias into logical plan node