VACMS-16726: Remove block_content_permissions from composer.

[Becapa]

Description

Relates to #16726.

QA steps

As an administrator

1. Browse to the extensions page (/admin/modules)
   • Validate that Block Content Permissions is no longer listed anywhere on the page.

Definition of Done

• Documentation has been updated, if applicable.
• Tests have been added if necessary.
• Automated tests have passed.
• Code Quality Tests have passed.
• Acceptance Criteria in related issue are met.
• Manual Code Review Approved.
• If there are field changes, front end output has been thoroughly checked.

Select Team for PR review

• CMS Team
• Public websites
• Facilities
• User support
• Accelerated Publishing

Is this PR blocked by another PR?

• DO NOT MERGE

Does this PR need review from a Product Owner

• Needs PO review

CMS user-facing announcement

Is an announcement needed to let editors know of this change?

• Yes, and it's written in issue ____ and queued for publication.
  • Merge and ping the UX writer so they are ready to publish after deployment
• Yes, but it hasn't yet been written
  • Don't merge yet -- ping the UX writer to write and queue content
• No announcement is needed for this code change.
  • Merge & carry on unburdened by announcements

[dsasser]

Looks good: