Fixes: #4498
# Checklist for submitter
If some of the following don't apply, delete the relevant line.
- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.
## Testing
- [x] Added/updated automated tests
- Added unit test
- Changed existing unit tests to accept empty array instead of null
- [x] QA'd all new/changed functionality manually
- Tested that Fleet UI > host details, returns `software: []` instead of
nothing.
- Tested that with exclude_software=false, software returns the full
array for host.
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Co-authored-by: Anthony Maxwell <133805840+Illbjorn@users.noreply.github.com>
