d7_field_formatter_settings should migrate the default view mode to default not full

Problem/Motivation

The d7_field_formatter_settings migration maps formatters used in full view mode to the default entity view display on the destination. This means that right now, the formatter migration rows of the same field are overriding each other's migrated configuration if the actual field has formatter data for both of these view modes on the source Drupal7 site.

Proposed resolution

Add a test case to the D7 fixture
Change d7_field_formatter_settings migration so that the default view mode is migrated correctly to a default display.

Remaining tasks

Patch
Review
Commit

User interface changes

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

N/A