Power port bulk edit: missing "set null" on maximum power draw / allocated power draw

[candlerb]

NetBox version

v3.5.4

Python version

3.8

Steps to Reproduce

1. Go to a device which has power ports
2. Click on the power ports tab
3. Click the checkboxes besides one or more (or all) ports
4. Use the bulk "Edit" facility, e.g. e.g. /dcim/power-ports/edit/?device=5&return_url=/dcim/devices/5/power-ports/
5. Try to set the Allocated Draw or Maximum Draw to null for all those ports

Expected Behavior

Be able to click "Set null" to unset the value

Observed Behavior

The "Set null" checkbox is missing. (And setting zero is not allowed).

WORKAROUND: edit each port individually, blank out the power draw fields individually, and save each one.