Message attributes are not accessible via `l10n.format_value("message.attribute")` - the method returns "message.attribute" instead of the expected attribute value. sample ftl ``` test-button = .value = Click Me .title = This is a test button .aria-label = Test button for accessibility ``` `l10n.format_value("test-button.value")` should return `"Click Me"` but instead just returns `"test-button.value"` looking at bundle `has_message` and `get_message`, the search is by `msg_id`, but the attributes are stored in `attributes` of a message without a way of retrieveing them.