refactor: use _onResize instead of IntersectionObserver

[vursen]

Description

Removes IntersectionObserver from FormLayout in favor of ResizeMixin's _onResize which is also triggered when the element's visibility changes as a result of display: none or any other method that completely removes the element from the render tree.

Part of #8583

Type of change

• Refactor

[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

[web-padawan]

LGTM. We probably can backport this to 24.6 and 24.5 for consistency.

[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 9ebf93b
error: could not apply 9ebf93b... refactor: use _onResize instead of IntersectionObserver (#8620)
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 9ebf93b
error: could not apply 9ebf93b... refactor: use _onResize instead of IntersectionObserver (#8620)
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 24.7.0.alpha10 and is also targeting the upcoming stable 24.7.0 version.