Sorting blanks depends on the column type

[axelstudios]

Describe the bug

• Sorting canonical columns alphabetically puts empty values at the end
• Sorting extra_data columns alphabetically puts empty values at the beginning

Expected Behavior
It should be consistent, not sure which we'd prefer

Actual Behavior
It sorts inconsistently

Steps to Reproduce

1. Import a csv like:

   PM Property ID,City,Extra
   1,A,A
   2,B,B
   3,,
   

2. Sort the City and Extra columns to observe the issue

[kflemin]

go with the canonical field sort since it's already that way?