ALT text describes image, not action

At LMS dashboard course listing the course cover has alt
attribute that have course name and then Cover Page it describe
image not the action which is to take user to course home page

TNL-1383

lms/templates/dashboard/_dashboard_course_listing.html

@@ -51,7 +51,7 @@ from student.helpers import (
     % if show_courseware_link:
       % if not is_course_blocked:
         <a href="${course_target}" class="cover">
-        <img src="${course_image_url(course)}" alt="${_('{course_number} {course_name} Cover Image').format(course_number=course.number, course_name=course.display_name_with_default) |h}" />
+        <img src="${course_image_url(course)}" alt="${_('{course_number} {course_name} Home Page').format(course_number=course.number, course_name=course.display_name_with_default) |h}" />
       </a>
         % else:
         <a class="fade-cover">