fix: Exclude Drag and Drop blocks from the link-scanning step in the Course Optimizer

[hinakhadim]

Description:

This PR resolves the issue where the Course Optimizer fails with a "Link Check Failed" error when a Drag and Drop block is present in a course.

JIRA Link
test-course: https://course-authoring.stage.edx.org/course/course-v1:edx+jrr_103+H2_2023/optimizer

Issue Details:

• The error occurred due to a TypeError: TypeError: expected string or bytes-like object, got 'dict'.
• This was caused by the data field in Drag and Drop blocks, which is stored as a dictionary instead of a string.
• The error was triggered in re.sub( , , xblock_data), where xblock_data expected a string but received an object.

Solution Implemented:

• The fix excludes Drag and Drop blocks from the link-scanning process in the Course Optimizer.
• This is done by checking the block type before processing its content.
• The solution ensures that the optimizer can successfully scan other course content without failure.

Testing & Verification:

• Verified the fix by running the optimizer on test courses with and without Drag and Drop blocks.
• Confirmed that the scan completes successfully and broken links are detected as expected.

How to verify locally

• Checkout this branch for edx-platform
• Export test-course from stage environment and import on local devstack
• run CMS and Cms-worker containers
• Run course optimizer on test-course

Before

After

[schenedx]

Instead of using keyword assert, you should follow the convention in this class to use self.assertFalse and other assert related functions.