fix: use correct selector for crud dialog overlay in Aura

[web-padawan]

Description

Fixed incorrect usage of vaadin-crud-dialog - that element is in shadow DOM.
Instead, vaadin-crud::part(overlay) is a correct way to target dialog's overlay.

Also added missing Aura visual test for crud editor (default, aside, bottom).

Type of change

• Bugfix

[vaadin-review-bot]

✅ Nothing to flag — the changes look good.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[vaadin-bot]

Hi @web-padawan and @web-padawan, when i performed cherry-pick to this commit to 25.1, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 32c6ad6
error: could not apply 32c6ad6... fix: use correct selector for crud dialog overlay in Aura (#12261)
hint: After resolving the conflicts, mark them with
hint: "git add/rm ", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".

[vaadin-bot]

This ticket/PR has been released with Vaadin 25.3.0-alpha8.