Feature request: Change interpretation of empty string depending on NOT NULL flag

Current behaviour:

Many of the text fields in my day-to-day database work are set to NOT NULL. If I erase the contents of a text string in the table row view, or in the detail sidebar, my intention is to insert the empty string into this field, but Postico is assuming I want to enter NULL and this triggers a validation error, meaning I cannot save the row. I then have to go back and explicitly choose "Empty String" from the dropdown menu next to the field.

Proposed behaviour:

If a field is marked NOT NULL, then when the user presses Enter in a text field containing no text, Postico should insert the empty string into the field.

Reproduce the behavior in the table row view and detail sidebar by clearing a text field marked NOT NULL and pressing Enter. Trace the UI path for the field value and validation, then verify that saving inserts an empty string for NOT NULL fields while the existing explicit NULL and Empty String choices remain available.

Written by the indexing model from the issue text.