XMLSchemaConverter incorrectly checks for supported metadata formats

[solth]

Describe the bug
In addition to the problem described in #5382, the (now obsolete) check for supported file formats also prevents other input metadata formats like EAD from being processed. These can now be configured as OTHER in the import configuration setup since #5313 but will lead to the error UnsupportedFormatException: No SchemaConverter found that supports OTHER and XML! during import.

To Reproduce
Steps to reproduce the behavior:

1. Configure an ImportConfiguration with metadata format OTHER
2. Try to import a record using the new ImportConfiguration

Expected behavior
Using import configurations with metadata format OTHER should not lead to an error.

Release
3.4.4-SNAPSHOT (Commit b65bd96)