Ignore usertype when searching for Common dir

[realVinayak]

Implements second solution in
#3956 (comment)

Note: This will cause unexpected behavior if resources with same name appears under multiple usertypes at Global level ("Common"). I don't know if that case happens or not.

@grantfitzsimmons Have you ever seen that?

Testing instructions:

These are specific to insectcollection_umn database on the test panel.

1. Create ExportFeed resource under the Global Resources, so at the top level. It is fine if the ExportFeed is empty:
   

2. Run the feed by clicking on "Create DwC Archive" in User Tools
   

3. This branch should "run" the feed (you will not get actual results till you set the feed correctly). However, xml-editor should give a notification with the error message saying "MissingFeedResource" somewhere in the crash report.

[maxpatiiuk]

👏

[emenslin]

Looks good, did not get the notification with the error message.

[grantfitzsimmons]

Note: This will cause unexpected behavior if resources with same name appears under multiple usertypes at Global level ("Common"). I don't know if that case happens or not.

@grantfitzsimmons Have you ever seen that?

I can't think of situations like this at the global level, but I would not endorse it.