Fix a load of warnings in the tests

Stub things out to make the tests not throw warnings, so we can see the actual
problems.

src/components/views/rooms/MessageComposerInput.js

@@ -760,5 +760,5 @@ MessageComposerInput.propTypes = {
     // attempts to confirm currently selected completion, returns whether actually confirmed
     tryComplete: React.PropTypes.func,
 
-    onInputStateChanged: React.PropTypes.func.isRequired,
+    onInputStateChanged: React.PropTypes.func,
 };