“battery can discharge to grid” is disabled on BTM stand-alone battery

[brtietz]

Describe the bug

It's not clear why we disabled “battery can discharge to grid" for stand alone batteries. Enable the same procedures for these checkboxes and paired batteries.

To Reproduce

Steps to reproduce the behavior:

1. Go to a behind the meter stand alone battery
2. Click on battery dispatch
3. Battery can discharge to grid is disabled

Expected behavior

This checkbox should follow the same behavior as paired BTM batteries.

Screenshots