Flat File Importer - selection of directory with pdfs causes designer to freeze.

In the Flat File Import Wizard, if a user selects a directory with mixed file types - this can cause Designer to freeze.

I created a connection profile with a directory containing about 60 files of various types. On the source selection page of the wizard, I selected the profile - then Designer hung.

The problem seems to be in TeiidMetadataFileInfo - the loadHeader method. The assumption is that the files being read are all text files - we need to detect and skip files of incompatible type.