Why does it say the mutation survives?

Stryker says that this mutation survives the tests

```diff
- ReactDOM.render(, document.getElementById('root'))
+ ReactDOM.render(, document.getElementById(""))
```

In

```
#0. [Survived] StringLiteral
/Users/gleb/git/cypress-mutation-example/src/index.js:4:49
- ReactDOM.render(, document.getElementById('root'))
+ ReactDOM.render(, document.getElementById(""))

Ran all tests for this mutant.
Ran 1.00 tests per mutant on average.
```

Start with src/index.js at line 4, column 49 and inspect the Cypress tests and mutation output around the surviving StringLiteral mutant. Reproduce the reported run, then determine whether the test suite exercises the affected React entry point; done means documenting the cause or providing a confirmed, actionable fix scope.

Written by the indexing model from the issue text.