test: replace onceResized with nextResize

[vursen]

Description

Replaces onceResized test helpers with nextResize, which subscribes to a real ResizeObserver instead of spying for internal component methods. Apart from cleaning up tests, this change also fixes Webkit failures in #8355.

Depends on

• feat: add nextResize helper to utils testing-helpers#13
• chore: upgrade @vaadin/testing-helpers to 1.1.0 #8388

Type of change

• Internal

[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 @vursen and @vursen, when i performed cherry-pick to this commit to 24.6, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 4af9e19
error: could not apply 4af9e19... test: replace onceResized with nextResize (#8387)
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]

Hi @vursen and @vursen, when i performed cherry-pick to this commit to 24.5, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick 4af9e19
error: could not apply 4af9e19... test: replace onceResized with nextResize (#8387)
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".