fix sink extraction issues fixes #498

[Darkere]

We keep getting reports with people extracting water instead of the request fluid through RS, so I figured a PR might speed up fixing this? ;)

This fixes the issue without changing what I think was the intended behavior.

If Sink requires water is set to true:

• Sink behaves like a simple tank

If Sink requires water is set to false:

• any fluid inserted will be voided
• extraction provides water or nothing* if a different fluid is requested

*unless the config was changed and a fluid was inserted before that