feat(icon): enable svg icons by default

[chintankavathia]

BREAKING CHANGE: icons are now rendered as SVG by default instead of icon fonts.

Applications that rely on icon fonts must explicitly opt out by using:

provideIconConfig({ disableSvgIcons: true })

• I confirm that this MR follows the contribution guidelines.

[gemini-code-assist]

Code Review

This pull request updates the default icon rendering to use SVGs and cleans up demo app configuration. While a functional improvement, enabling SVG icons by default introduces a critical Cross-Site Scripting (XSS) vulnerability due to unsanitized SVG content. Furthermore, a critical issue with unit tests needs to be resolved.

[github-actions]

Documentation.
Examples.
Playwright report.

Coverage Reports:

• element-ng
• element-translate-ng

[spike-rabbit]

Lets wait if we can have the icons as CSS masks.

[spike-rabbit]

Code-wise everything is good. I just think we should chnange the breaking change note. Otherwise I am afraid we spook people out.
I guess something like this might be better:

---

BREAKING CHANGE: <si-icon> now renders icons by default as SVG instead of using the icon-font. element-* icon classes are not affected by this change.

SVG icons render slightly differently so VRT snapshots may need to be updated.

To restore the previous behavior, opt-out SVG icons.

  provideIconConfig({ disableSvgIcons: true })

[spike-rabbit]

👍

[github-actions]