"Save file as" dialogues should not show "all supported file types"

[jeroens]

The EwE UI is trying to be a bit too smart. File Dialogs, by default, aggregate all file extensions to show "all supported file formats". This is handy when loading files, but should not appear when saving files. This filter item is not usable in the save dialogs.

Using this item results in internal warnings, and the selection of the first file extent. This is rather unexpected, but the file save is handled correctly from here on