feat: make sqrt constants

[dmnsgn]

The previous PR actually only fixed 2 of the 4 warnings in rollup. Somehow the REPL online is not reporting them (as you can see from the links in that comment earlier) although I am using the same 4.18.1 rollup version locally. So apologies for the second PR in a row, the repl wasn't enough 😕 But I have tested with a real use case now.

Here I have extracted the two sqrt calls into const which has two benefits:

• performance/size: saves a few bytes when tested with terser (when using noise 2D and noise 4D, noise 3D is not using the sqrts' so nothing more is eliminated)
• actually fix rollup annotation warnings

[jwagner]

No worries, I didn't catch it either. It's a bit late now but I'll have a look later. :)

[jwagner]

Released in 4.0.3. Thanks again @dmnsgn. :)