Random effect should be configurable to also use White in RGBW lights

**Describe the problem you have/What new integration you would like**
[Galaxy projectors](https://www.google.com/search?q=galaxy+projector&udm=2) have RGBW lights that refract in various interesting patterns. The White LED in them isn't just an alternative to R+G+B, it's rather an additional color that can be used in various combinations (e.g. White + Red).

**Please describe your use case for this integration and alternatives you've tried:**

In theory, all channels can mapped to separate lights with separate effects, but that'd just make things a bit more awkward for the user.

Ideally it should be possible to configure the effect to use all four channels.

**Additional context**

Code in question: https://github.com/esphome/esphome/blob/b82666002dc55b60b3e7f3f2549c0bf8a0203f91/esphome/components/light/base_light_effects.h#L74-L79

Right now it just randomizes R, G and B, but it should be configurable to also set a random value to the white led.