fix(db-postgres): ensure deletion of numbers and texts in upsertRow

[akhrarovsaid]

What?

This PR fixes an issue while using text & number fields with hasMany: true where the last entry would be unreachable, and thus undeletable, because the transformForWrite function did not track these rows for deletion. This causes values that should've been deleted to remain in the edit view form, as well as the db, after a submission.

This PR also properly threads the placeholder value from admin.placeholder to text & number hasMany: true fields.

Why?

To remove rows from the db when a submission is made where these fields are empty arrays, and to properly show an appropriate placeholder when one is set in config.

How?

Adjusting transformForWrite and the traverseFields to keep track of rows for deletion.

Fixes #11781

Before:

Editing---Post-dbpg-before--Payload.webm

After:

Editing---Post--dbpg-hasmany-after-Payload.webm

[r1tsuu]

This misses integration tests that point at what was fixed.

[akhrarovsaid]

Hey @r1tsuu

Thanks for the feedback! I've gone ahead and added two hasMany tests - one for number and one for text fields. Let me know if this is sufficient here, or you'd like more thorough tests.

Thank you!

[r1tsuu]

Awesome

[r1tsuu]

Looks good to me, let's also hear @DanRibbens's feedback.