Field widget doesn't allow to set initial stock level if purchasable entity hasn't been created

The patch doesn't work anymore on D10 because the query is missing an access check and it's not visible that it fails as the exception is silently ignored further up in the chain.

Manually edited the patch to fix that.

The patch in #10 works for me.

I was not sure about the setting of the adjustment to zero in the postSave but after review and testing, I can not find a good reason not to.
Commit as is and thank you @Berdir for the work and @Lukas von Blarer
for testing

Automatically closed - issue fixed for 2 weeks with no activity.

I had problems using the patch merged to master.
While it solves problems, there were some cases that the AccessCheck(TRUE) occurred problematic behavior.

Submitting a patch which makes AccessCheck from TRUE to FALSE.

Have a nice day