fix: problem editor content style

[ihor-romaniuk]

Description

This pull request contains styling fixes of content editor for Problem xblock. For fields Question, Answers, Feedback, Hints:

• [1] Heading 3, Heading 4, Heading 5, Heading 6
• [2] Numbered list is displayed without numbers

Related Pull Requests

PR to the redwood branch: #34869
PR to the master branch: #34867

Screenshots before:

[1]	[1]	[2]	[2]

Screenshots after:

[1]	[1]	[2]	[2]

Steps to Reproduce:

1. Enable new problem editor and sharing by adding in /admin/waffle/flag/

• new_core_editors.use_new_problem_editor

2. In studio open unit -> add new component -> Problem -> Single / Multiple select
3. Check problem displaying

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