ROENROLL-1508 fix add course to non-primary plan

src/app/degree-planner/store/effects/course.effects.ts

@@ -131,8 +131,11 @@ export class CourseEffects {
       const { subjectCode, termCode, courseId, newIndex } = action.payload;
       let addCourse$: Observable<CourseBase>;
 
-      // When adding to an active term use cart endpoint
-      if (activeTerms.find(term => term.equals(termCode))) {
+      const isActiveTerm = activeTerms.filter(term => term.equals(termCode));
+      const isPrimaryPlan = visibleDegreePlan
+        ? visibleDegreePlan.primary
+        : false;
+      if (isActiveTerm && isPrimaryPlan) {
         addCourse$ = this.api.addCourseToCart(subjectCode, courseId, termCode);
       } else {
         addCourse$ = this.api.addCourse(