removed unused velocity from test config

tests/configs/earth_mars_simple.toml

@@ -35,7 +35,6 @@ radius = 1000.0
 # Position at LEO altitude: Earth position + (Earth radius + 200km altitude)
 # Earth: 1.496e11, LEO offset: 6.571e6, Total: 1.49606571e11
 position = { x = 1.49606571e11, y = 0.0, z = 0.0 }
-velocity = { x = 0.0, y = 0.0, z = 0.0 }
 parent_index = 1
 color = { r = 1.0, g = 0.0, b = 0.5 }
 eccentricity = 0.0