feat: add cohort filter in filter action bar (#172)

* feat: add cohort filter in the filter action bar

* test: fix posts view fail test cases

* test: add test case for cohort filter

src/discussions/posts/data/thunks.js

@@ -122,6 +122,9 @@ export function fetchThreads(courseId, {
   if (filters.search) {
     options.textSearch = filters.search;
   }
+  if (filters.cohort) {
+    options.cohort = filters.cohort;
+  }
   return async (dispatch) => {
     try {
       dispatch(fetchThreadsRequest({ courseId }));