Fix UI errors

...ations/0109_districtarticlepage_mastodon_feed_and_more.py

district/templates/district/base.html

senate/migrations/0006_senatehomepage_mastodon_feed.py

senate/templates/senate/base.html

shared/blocks.py

shared/models.py

shared/templates/shared/blocks/mastodon_feed_block.html

shared/templates/shared/mastodon_feed_link_snippet.html

shared/templates/shared/mastodon_feed_snippet.html

shared/templates/shared/mastodon_icon_snippet.html

shared/templatetags/shared_filters.py

...grations/0042_uniwebarticlepage_mastodon_feed_and_more.py

uniweb/templates/uniweb/base.html