fix: load Image/IFrame sources when disabled

[mcollovati]

When an Image or IFrame backed by a DownloadHandler lives inside a disabled component, the browser receives a 403 and the resource never loads.

Image.setSrc(DownloadHandler) and IFrame.setSrc(DownloadHandler) now allow the resource to be served regardless of the owner's enabled state, since these sources are fetched passively as part of rendering rather than as a user action.

Fixes #22772

[sonarqubecloud]

Quality Gate passed

Issues
2 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

[mcollovati]

Follow-up needed in vaadin/flow-components: if this PR gets merged, components that accept a DownloadHandler as a display-only source (e.g. SvgIcon.setSrc) should call .allowDisabled() on it before registering it on the element, so the resource keeps loading when the owning component is disabled (like what Image.setSrc now does).

[github-actions]

Test Results

 1 410 files  + 2   1 410 suites  +2   1h 23m 43s ⏱️ + 1m 7s
10 160 tests +10  10 090 ✅ +10  70 💤 ±0  0 ❌ ±0 
10 635 runs  +10  10 556 ✅ +10  79 💤 ±0  0 ❌ ±0 

Results for commit 9aefbb0. ± Comparison against base commit 2e3d63f.

[vaadin-bot]

Hi @mcollovati and @Artur-, when i performed cherry-pick to this commit to 24.10, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick e1d46ea
error: could not apply e1d46ea... fix: load Image/IFrame sources when disabled (#24346)
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 @mcollovati and @Artur-, when i performed cherry-pick to this commit to 25.0, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick e1d46ea
error: could not apply e1d46ea... fix: load Image/IFrame sources when disabled (#24346)
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 @mcollovati and @Artur-, when i performed cherry-pick to this commit to 24.9, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick e1d46ea
error: could not apply e1d46ea... fix: load Image/IFrame sources when disabled (#24346)
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 25.2.0-alpha8.