eslint-plugin-react-hooks version: 4.2.0

## Steps To Reproduce

I know it shouldn't exist in production code, but it's annoying while editing some files.

```js
import React, { useEffect } from "react";

const App = () => {
  useEffect(); // <-
  return null;
};

export default App;
```

Link to code example: https://codesandbox.io/s/polished-sun-3wr27?file=/src/App.js

## The current behavior

ESLint crashed.

```
TypeError: Cannot read property 'type' of undefined
```

## The expected behavior

ESLint doesn't crash but reports an error instead.
const callbackIndex = getReactiveHookCallbackIndex(node.callee, options);
      if (callbackIndex === -1) {
        
        return;
      }
      const callback = node.arguments[callbackIndex];
      const reactiveHook = node.callee;
      const reactiveHookName = getNodeWithoutReactNamespace(reactiveHook).name;
      const declaredDependenciesNode = node.arguments[callbackIndex + 1];
      const isEffect = /Effect($|[^a-z])/g.test(reactiveHookName);
      
      
      
      if (!declaredDependenciesNode && !isEffect) {
        
        if (
          reactiveHookName === 'useMemo' ||
          reactiveHookName === 'useCallback'
        ) {
          
          reportProblem({
            node: reactiveHook,
            message:
              `React Hook ${reactiveHookName} does nothing when called with ` +