Allow SGA blocks to be used in Libraries v2 context [FC-0076]

[pomegranited]

What are the relevant tickets?

Part of: openedx/frontend-app-authoring#1514
Private-ref: FAL-4032

What's this PR do?

Fixes errors thrown when previewing/editing SGA blocks in a Libraries v2 context.

How should this be manually tested?

To verify the issues fixed here:

1. Ensure that edx_sga is in the list of LIBRARY_SUPPORTED_BLOCKS configured for your Authoring MFE.
2. Import the Open edX Demo course into your tutor dev stack (tutor dev do importdemocourse)
3. Navigate to the Open edX Demo course and locate the Staff Graded Assignment (sga) block.
4. Copy the SGA block to your staging clipboard.
5. Go back to the Authoring MFE home page, and create a new content library.
6. Paste the copied SGA component into your library.
7. Click on the SGA card to display its Preview in the sidebar, and/or click Expand to view it in a modal.
8. Click "Edit Component" to edit the SGA block.

To test this fix:

1. Install this branch in your CMS, e.g. tutor dev exec cms pip install git+https://github.com/mitodl/edx-sga.git@refs/pull/363/head
2. Repeat the verification steps above while watching the CMS logs.
3. Ensure the SGA Preview shows the same content that was displayed for the SGA block in the course.
4. Ensure that you can edit and save changes to the library SGA block from within the library context.

Screenshots

[Anas12091101]

@pomegranited could you please rebase this PR?

[Anas12091101]

I have tested this locally and everything LGTM 👍 . Thanks @pomegranited for making these changes