translate class ignored after seeing notranslate

[jelmervdl]

Describe the bug
Elements with a notranslate class are ignored by InPageTranslation. Websites like Mastodon also seem to use this to get around issues with Google Translate. However, they also mark elements that they do want translated with a translate class. Firefox Translations ignores that class at the moment.

To Reproduce
Have a page with something like this:

<p class="notranslate">
  Könnte es dieses Element bitte ignorieren?
  <span>Das wäre toll.</span>
  <span class="translate">Aber bitte übersetzen Sie diesen Satz.</span>
</p>

If you translate that page then with Google Chrome, only the last sentence will be translated. If you translate it with Firefox Translations, it doesn't.

Expected behavior
Translate elements that are marked with class="translate" when they appear inside an class="notranslate" or translate="no" element.

Desktop (please complete the following information as possible):

• Firefox Browser version: 107.0
• Processor information: Intel x86
• OS version: macOS 13.0.1
• System type (32-bit or 64-bit): 64bit
• Firefox Translation Extension version: 1.2.0buildid20221114.185738
• Webpage on which issue was observed: Any up-to-date Mastodon instance
• Language of the webpage: n/a
• Translating to (language): n/a
• Console logs from Web Developer Tools: n/a

Additional context
I haven't been able to find any documentation for Google Translate that says that class="translate" should work. But empirically it does.

[marco-c]

Moved to Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1842814.