feat: Add feature flag for enabling/disabling anonymous question posting

[GeorginaFraire]

What does this PR do?

introduces a new feature flag named postAnonymousQuestions that allows toggling the ability to post questions anonymously. The flag is implemented to control the visibility of the anonymousposting feature, giving flexibility to enable or disable it.

Where should the reviewer start?

• verify that the postAnonymousQuestions is false

How should this be manually tested?

1. Log in.
2. Navigate to the page to create a new question (click on 'Ask Question').
3. Ensure that you do not see the option to post an anonymous question.
4. Create a question.
5. Open the file `` and modify the value of postAnonymousQuestions to true.
6. Repeat step 2.
7. You should now see the option to post anonymous questions.
8. Create a question (both anonymous and non-anonymous).

Any background context you want provide?

we want to temporary restrict the option to post anonymous questions.

What are the relevant tickets?

Closes #291

Screenshots

[feature flag: postAnonymousQuestions : false ]

[feature flag: postAnonymousQuestions : true ]