ECA Access: Incorrect field name in "Determining entity field access" plugin

Here's a trivial patch.

I've asked this before at #3417097-4: Errors thrown during cron when delayed actions are not yet due for processing → : can you please provide contributions as MRs? This is now more important than before because that will run the tests. Also, bug fixes always go against the latest release, i.e. 2.0.x and will then be back ported, if applicable.

Due to project time constraints and needing a stable patch to apply via Composer, I figured to share the patch here, rather than just keep it local to the project.

I'll provide an MR as time permits.

Fixed and backported.

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