MOBILE-1927 calendar: Fix no groups message

src/assets/lang/en.json

@@ -1391,7 +1391,7 @@
     "core.course.warningmanualcompletionmodified": "The manual completion of an activity was modified on the site.",
     "core.course.warningofflinemanualcompletiondeleted": "Some offline manual completion of course '{{name}}' has been deleted. {{error}}",
     "core.coursedetails": "Course details",
-    "core.coursenogroups": "This course doesn't have any group.",
+    "core.coursenogroups": "You are not a member of any group of this course.",
     "core.courses.addtofavourites": "Star this course",
     "core.courses.allowguests": "This course allows guest users to enter",
     "core.courses.availablecourses": "Available courses",

src/lang/en.json

@@ -48,7 +48,7 @@
     "copiedtoclipboard": "Text copied to clipboard",
     "course": "Course",
     "coursedetails": "Course details",
-    "coursenogroups": "This course doesn't have any group.",
+    "coursenogroups": "You are not a member of any group of this course.",
     "currentdevice": "Current device",
     "datastoredoffline": "Data stored in the device because it couldn't be sent. It will be sent automatically later.",
     "date": "Date",