prevent exe from being added to another team when installer already exists and no scripts provided (#28718)

> For #28558, part 2

# Checklist for submitter

If some of the following don't apply, delete the relevant line.

<!-- Note that API documentation changes are now addressed by the
product design team. -->

- [x] Added/updated automated tests
- [x] A detailed QA plan exists on the associated ticket (if it isn't
there, work with the product group's QA engineer to add it)
- [x] Manual QA for all new/changed functionality
- [x] For unreleased bug fixes in a release candidate, confirmed that
the fix is not expected to adversely impact load test results or alerted
the release DRI if additional load testing is needed.

ee/server/service/software_installers.go

@@ -1761,6 +1761,16 @@ func (svc *Service) softwareBatchUpload(
 						continue
 					}
 
+					if i.Extension == "exe" {
+						if p.InstallScript == "" {
+							return errors.New("Couldn't edit. Install script is required for .exe packages.")
+						}
+
+						if p.UninstallScript == "" {
+							return errors.New("Couldn't edit. Uninstall script is required for .exe packages.")
+						}
+					}
+
 					installer.Extension = i.Extension
 					installer.Filename = i.Filename
 					installer.Version = i.Version