Using Manifest Editor to open AndroidManifest.xml containing service only will cause file corruption

If someone is trying to build android project that contains only service, it is not possible to use Manifest Editor to edit manifest fields. The manifest file is completely valid and it is possible to use that to build a proper APK (needs to be signed with platform certificate)

Reproduction steps:
1. Try to open AndroidManifest.xml file from attachment using Qt Creator Manifest Editor.
2. Parse error will occur, and file will be malformed:

Workaround:
Use only text editor

Expected result:
1. Ideal solution: Qt Creator Manifest Editor allows to do GUI based edits of any kind of AndroidManifest.xml file
2. Good enough solution: don't malform the file, disable all inputs in Manifest Editor widgets, display information that only text editor is supported for manifests that don't contain activities.