Remove html-sanitizer custom attrs workaround

Fix merged upstream (1.7.2).

TODO.md

@@ -62,7 +62,6 @@
 - Waiting for approval/release
   - nio avatars
   - olm/olm-devel 0.3.1 in void repos
-  - html-sanitizer allowed attributes fix pypi release
 
 - Distribution
   - Review setup.py, add dependencies

harmonyqml/backend/html_filter.py

@@ -28,10 +28,6 @@ class HtmlFilter(QObject):
         sanitizer.normalize_overall_whitespace         = lambda html: html
         sanitizer.normalize_whitespace_in_text_or_tail = lambda el: el
 
-        # Prevent custom attributes from being removed
-        sanitizer.lxml.html.clean.Cleaner.safe_attrs |= \
-            self.sanitizer_settings["attributes"]["font"]
-
         # hard_wrap: convert all \n to <br> without required two spaces
         self._markdown_to_html = mistune.Markdown(hard_wrap=True)