MOBILE-2900 courses: Exclude enrolled user count from WS call

src/classes/site.ts

@@ -176,7 +176,8 @@ export class CoreSite {
         3.3: 2017051503,
         3.4: 2017111300,
         3.5: 2018051700,
-        3.6: 2018120300
+        3.6: 2018120300,
+        3.7: 2019030700 // @todo: Replace it with the right 3.7 date when released
     };
 
     // Rest of variables.

src/core/courses/providers/courses.ts

@@ -682,14 +682,19 @@ export class CoreCoursesProvider {
         return this.sitesProvider.getSite(siteId).then((site) => {
 
             const userId = site.getUserId(),
-                data = {
+                data: any = {
                     userid: userId
                 },
                 preSets = {
                     cacheKey: this.getUserCoursesCacheKey(),
+                    getCacheUsingCacheKey: true,
                     omitExpires: !!preferCache
                 };
 
+            if (site.isVersionGreaterEqualThan('3.7')) {
+                data.returnusercount = 0;
+            }
+
             return site.read('core_enrol_get_users_courses', data, preSets);
         });
     }