Removed a non supported parameter from the docstring (#23651)

The `opacity` parameter is not valid for LineBasicMaterial, it's also not mentioned in the documentation.
But this was mentioned in the parameters docstring, which VSCode also provides as a possible suggestion.

src/materials/LineBasicMaterial.js

@@ -4,8 +4,6 @@ import { Color } from '../math/Color.js';
 /**
  * parameters = {
  *  color: <hex>,
- *  opacity: <float>,
- *
  *  linewidth: <float>,
  *  linecap: "round",
  *  linejoin: "round"