When an anchor scroll happens, we run document.querySelector. This value can be taken directly from the user. Therefore it's possible to throw an error on scrolling, which can cause the application to fail.
This PR escapes the selector before using it.
Related to #28193
[Internal discussion](https://groups.google.com/a/google.com/forum/#!topic/angular-users/d82GHfmRKLc)
PR Close#29577
