fix: return a 403 instead of a redirect from course_home_api api methods (#32210)

* fix: return 403 on course access error rather than redirect

lms/djangoapps/course_home_api/utils.py

@@ -0,0 +1,24 @@
+""" Utilities for views in the course home api"""
+from rest_framework.exceptions import PermissionDenied
+
+from lms.djangoapps.courseware.courses import get_course_with_access as base_get_course_with_access
+from lms.djangoapps.courseware.exceptions import CourseAccessRedirect
+
+
+def get_course_or_403(*args, **kwargs):
+    """
+    When we make requests to the various Learner Home API endpoints, we do not want to return the actual redirects,
+    Instead we should return an error code. The redirect info is returned from the course metadata endpoint and the
+    URL can be followed by whatever client is calling.
+
+    Raises:
+     - 404 if course is not found
+     - 403 if the requesting user does not have access to the course
+    """
+    try:
+        return base_get_course_with_access(*args, **kwargs)
+    except CourseAccessRedirect as e:
+        raise PermissionDenied(
+            detail=e.access_error.user_message,
+            code=e.access_error.error_code
+        ) from e