Fix incorrect access check in WebformSubmissionExporter::generate

Problem/Motivation

This is a regression that I introduced in #3296061: Relying on entity queries to check access by default is deprecated, I think, the exporter should not do an access check.

https://git.drupalcode.org/project/webform/-/commit/4786f7dd5d56cbdf593d... then attempts to undo that by adding an accessCheck(FALSE) on the getQuery() method, but generate() overwrites that again.

I'm slightly confused about the whole thing, as access checks are enabled by default, and it actually makes sense to me that this is the case, but I'm actually seeing a test fail as we have a feature that allows users to export submissions just for their source entity who otherwise don't have view permissions for the whole form. This works on 6.1 and it doesn't work on 6.2.

Steps to reproduce

Proposed resolution

Remove that call again.

Remaining tasks

User interface changes

API changes

Data model changes