bring back null check (#1940)

Undo the removal in
#1933
- as there is a chance that this is a separate issue.

msal/src/main/java/com/microsoft/identity/client/AccountAdapter.java

@@ -60,7 +60,9 @@ public List<ICacheRecord> filter(@NonNull List<ICacheRecord> records) {
                 final String acctHomeAccountId = cacheRecord.getAccount().getHomeAccountId();
                 final String acctLocalAccountId = cacheRecord.getAccount().getLocalAccountId();
 
-                if (!acctHomeAccountId.contains(acctLocalAccountId)) {
+                // TODO: check the logic on broker side to make sure this value is NOT null.
+                if (acctLocalAccountId != null &&
+                        !acctHomeAccountId.contains(acctLocalAccountId)) {
                     result.add(cacheRecord);
                 }
             }