feat: Use legacy_web_url to redirect to legacy courseware (#404)

As part of making the new courseware experience the
default for staff, the LMS /jump_to/ links that are
exposed by the Course Blocks API via the `lms_web_url`
field will soon direct users to whichever experience
is active to them (instead of always directing to
the legacy experience & relying on the learner
redirect).

Because of this, the MFE can no longer rely on
`lms_web_url` to land a staff user to the legacy
experience. However, the aformentioned change
will also introduce a `legacy_web_url` field
to the API, which we *can* use for this purpose.

TNL-7796

src/courseware/data/api.js

@@ -38,7 +38,8 @@ export function normalizeBlocks(courseId, blocks) {
           effortTime: block.effort_time,
           id: block.id,
           title: block.display_name,
-          lmsWebUrl: block.lms_web_url,
+          // Fall back to `lms_web_url` until `legacy_web_url` is added to API (TNL-7796).
+          legacyWebUrl: block.legacy_web_url || block.lms_web_url,
           unitIds: block.children || [],
         };
         break;
@@ -47,7 +48,8 @@ export function normalizeBlocks(courseId, blocks) {
           graded: block.graded,
           id: block.id,
           title: block.display_name,
-          lmsWebUrl: block.lms_web_url,
+          // Fall back to `lms_web_url` until `legacy_web_url` is added to API (TNL-7796).
+          legacyWebUrl: block.legacy_web_url || block.lms_web_url,
         };
         break;
       default: