fix: use the most recent IntersectionObserver entry in form-layout

[web-padawan]

Description

Fixes #8564

I was unable to come up with a reliable test for this since the case where IntersectionObserver entries accumulate between callback invocations generally requires some slow rendering, like in the reproduction example provided.

Type of change

• Bugfix

[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

[vursen]

Just for reference: We are considering dropping IntersectionObserver completely in #8590. It seems to become unnecessary when FormLayout is based on CSS grid. However, the investigation is still ongoing.

[vaadin-bot]

Hi @web-padawan and @web-padawan, 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 f047f75
error: could not apply f047f75... fix: use the most recent IntersectionObserver entry in form-layout (#8596)
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 @web-padawan and @web-padawan, 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 f047f75
error: could not apply f047f75... fix: use the most recent IntersectionObserver entry in form-layout (#8596)
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.alpha7 and is also targeting the upcoming stable 24.7.0 version.