fix(lint): Removes unintended no-mixed-interface rule.

Author: ryasmi

configs/tslint.json

@@ -11,7 +11,7 @@
     "no-let": true,
     "no-this": true,
     "no-class": true,
-    "no-mixed-interface": true,
+    "no-mixed-interface": false,
     "no-expression-statement": false,
     "adjacent-overload-signatures": true,
     "ban-types": false,