[style] Fix memory leak

[oliviertassinari]

This is not good 🙈. We had sheets.js keeping a reference to all the create sheets. This can be an important leak.

When calling createStyleSheet(), a StyleSheet is created. The constructor is adding itself to jss/sheets.js. But it's not removed when calling .detach().

So, we need to call removeStyleSheet() to be detached from jss/sheets.js.

Closes #8019

• PR has tests / docs demo, and is linted.
• Commit and PR titles begin with [ComponentName], and are in imperative form: "[Component] Fix leaky abstraction".
• Description explains the issue / use-case resolved, and auto-closes the related issue(s) (http://tr.im/vFqem).

[oliviertassinari]

@kof. I do think that react-jss has the same issue given
https://github.com/cssinjs/react-jss/blob/master/src/createHoc.js#L91 and https://github.com/cssinjs/jss/blob/master/src/SheetsManager.js#L52.