drivesetup: Be less assertive on unknown filesystem types

* This condition here is "we are unaware of this filesystem
  or it is not formatted"
* Since a filesystem could exist, we don't want to falsely
  guide users that data doesn't exist within a partition,
  when it could actually exist.
* In this case, I had a bcachefs filesystem, which showed
  in DriveSetup as "Not formatted (Linux data)"
* With this change, the language adjusts to "Unknown (Linux data)"

Change-Id: Ib88fea16ee9403419d54bb5223ceee950591ce56
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7540
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Reviewed-by: humdinger humdinger <humdinger@mailbox.org>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

src/apps/drivesetup/PartitionList.cpp

@@ -306,7 +306,7 @@ PartitionListRow::PartitionListRow(BPartition* partition)
 		SetField(new BStringField(kUnavailableString), kVolumeNameColumn);
 	} else {
 		if (!partitionType.IsEmpty()) {
-			partitionType.SetToFormat(B_TRANSLATE("Not formatted (%s)"),
+			partitionType.SetToFormat(B_TRANSLATE("Unknown (%s)"),
 				partitionType.String());
 			SetField(new BStringField(partitionType), kFilesystemColumn);
 		} else