Fix warning message to be less "scary"

[woodiertexas]

trafficstars

All I did was make it use the success styling found in the "Powerful" message box on the main site. I also was unable to test this locally because of this: https://mclo.gs/wr6vtB4

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See preview on Cloudflare Pages: https://preview-176.quiltmc-org.pages.dev

[ix0rai]

not a fan. making it green is misleading, and the motion graphic is super annoying. I'd personally like to make the box yellow with #173

[woodiertexas]

Going to figure out how to remove that "graphic" btw

[woodiertexas]

This was rather annoying to fix ngl:

[ix0rai]

imo this looks quite a bit worse on light mode

[UpcraftLP]

Seems like this would need to be changed in https://github.com/QuiltMC/quilt-bulma/blob/6a55ad3f40587198959b4c4e28468f6002954344/sass/common/colours.scss#L8 instead.

I think merging this to change the message style from danger to warning is fine however.