Also consolidate Tesla mocks into the HttpRequestMock module.
Tests were not exercising the real codepaths. The Rich Media Preview only works with https, but most of these tests were only mocking http.
Elixir 1.13 does not allow them in raw form anymore, resulting in errors
like this when running the test:
== Compilation error in file test/pleroma/web/rich_media/parser_test.exs ==
** (SyntaxError) test/pleroma/web/rich_media/parser_test.exs:136:45: invalid bidirectional formatting character in string: \u202C. If you want to use such character, use it in its escaped \u202C form instead
Mark Felder