Fix: avoid innerHTML to prevent CSP violations in Video Filters

[abhijeetnardele24-hash]

Fixes #4374

This PR resolves the TrustedHTML / CSP violations that were causing the Video Filters feature (introduced in #4112) to fail on YouTube.

Changes:

• Replaced the direct innerHTML string assignment in appearance.js with standard DOM API methods (document.createElementNS, setAttribute, etc.) when building the SVG <filter> and its <feConvolveMatrix> / <feComponentTransfer> children.
• This ensures the browser safely processes the elements without triggering Content Security Policy or TrustedHTML sinks.

Tested and verified that presets (e.g. Vivid) now correctly apply the filters to the video player without throwing console errors.

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[hkzo]

Thank you for the quick fix!
The reported error seems to be resolved on both Firefox and Chrome.

However, I found a couple of new issues:

• After applying a filter (e.g., using a preset), turning Activate OFF does not revert/reset the video back to normal.
• After applying a filter, clicking the filter button in the video player shows a "Filter OFF" notification, but the filter is not actually turned off. Clicking it a second time still displays "Filter OFF" and fails to toggle.

Could you please look into these issues when you have time?

[abhijeetnardele24-hash]

Thank you for the quick fix! The reported error seems to be resolved on both Firefox and Chrome.

However, I found a couple of new issues:

• After applying a filter (e.g., using a preset), turning Activate OFF does not revert/reset the video back to normal.
• After applying a filter, clicking the filter button in the video player shows a "Filter OFF" notification, but the filter is not actually turned off. Clicking it a second time still displays "Filter OFF" and fails to toggle.

Could you please look into these issues when you have time?

Yes sure

[ImprovedTube2]

@DivyaRaval1909 #4376

[hkzo]

Thank you @abhijeetnardele24-hash for being ready to look into this! The follow-up issues have been addressed in #4376

[ImprovedTube2]

Merged #4376 as of @hkzo's review.

Merging #4375 with no changes for now.
Should some of your edit remain? is some of it better by chance? @abhijeetnardele24-hash

Thanks!