I'm not really sure what the "symptoms" are, there aren't any errors, and looking at the particle sprite data, it does seem to find the correct texture file. Putting a print statement in the tick method of the particle shows that it does run, though nothing appears in-game. Perhaps the uv coordinates are incorrect, I'm not sure. Here's the sprite data:
TextureAtlasSprite{name='radiantmagic:particle/light_particle', frameCount=1, x=224, y=96, height=16, width=16, u0=0.875, u1=0.9375, v0=0.375, v1=0.4375}