Display error when using HTML filter in unsupported browser

[Stevoisiak]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

If a user adds an HTML filter to their filters in a browser that doesn't support HTML filtering, (ie: Chromium), an error or notice should be displayed informing the user that the filter is unsupported in their browser.

A specific URL where the issue occurs.

https://www.britannica.com/

Steps to Reproduce

1. Open Brave
2. Open the uBO dashboard
3. In My Filters, add www.britannica.com##^.category-link-CHATBOT

Expected behavior

uBO shows an error that HTML filters are unsupported in Chromium. This would look similar to the "trusted source" error.

Troubleshooting information

uBlock Origin: 1.74.0
Chromium: 151
filterset (summary):
 network: 182095
 cosmetic: 43629
 scriptlet: 37528
 html: 0
listset (total-discarded, last-updated):
 default:
  user-filters: 0-0, never
  ublock-filters: 53091-87, 3m
  ublock-badware: 10250-17, 3m
  ublock-privacy: 4136-4, 3m
  ublock-unbreak: 2803-1, 3m
  ublock-quick-fixes: 503-0, 3m
  easylist: 86360-484, 3m
  easyprivacy: 56438-734, 3m
  urlhaus-1: 47615-5, 3m
  plowe-0: 3518-0, 3m
filterset (user): [array of 1 redacted]
userSettings: [none]
hiddenSettings: [none]
supportStats:
 allReadyAfter: 958 ms (selfie)
 maxAssetCacheWait: 81 ms
 cacheBackend: indexedDB

[gorhill]

Related: #2964. Without fixing this related issue, showing response body-modifying filters as error on unsupported platforms would drown other errors -- we have over 400 response body-modifying filters in uBO's own lists.