XML schema validation interrupts EAD file upload

[solth]

Describe the bug
The import of EAD records using the file upload is currently not possible because the XML schema validation added in Kitodo 4.0 tries to validate the individual collection and file XML snippets parsed from the originally uploaded, complete XML file. Concerning the XML schema definition, these snippets are not schema complete and should not validated by the system.

To Reproduce
Steps to reproduce the behavior:

1. Configure an import configuration of type "File upload" and with metadata format EAD
2. Try to create processes by uploading an EAD XML file with this import configuration
3. See (misleading) validation error

Expected behavior
XML schema validation should only check the uploaded XML file in its entirety, not the individual parts that Kitodo extracts from it.

Release
4.0.1, current main branch

Additional context
Add any other context about the problem here.