Remove bibliotron-article (#626)

Removes `bibliotron-article` class, which also fixes line number alignment issue on article passages

LC-1082 (subtask of LC-596)
LC-1072

Author: nedredmond

Reviewers: jeremywiebe, nedredmond

Required Reviewers:

Approved By: jeremywiebe

Checks: ✅ finish_coverage, ✅ Publish npm snapshot (ubuntu-latest, 16.x), ✅ Extract i18n strings (ubuntu-latest, 16.x), ✅ Lint, Typecheck, and Test (ubuntu-latest, 16.x), ✅ Check builds for changes in size (ubuntu-latest, 16.x), ✅ Cypress Coverage (ubuntu-latest, 16.x), ✅ Check for .changeset file (ubuntu-latest, 16.x), ✅ gerald, ✅ Jest Coverage (ubuntu-latest, 16.x)

Pull Request URL: #626

.changeset/perfect-windows-listen.md

@@ -0,0 +1,6 @@
+---
+"@khanacademy/perseus": minor
+"@khanacademy/perseus-editor": minor
+---
+
+Remove functionality of `useNewStyles` prop on `ArticleRenderer`