[WebGLUniforms] Removed unnecessary PureArrayUniform.updateCache method

[RenaudRohlinger]

The uniform array caching system has been changed but the method PureArrayUniform.updateCache is still there.

[RenaudRohlinger]

Also it seems that Uniforms Array cannot be updated dynamically anymore (#14045 was removed)

For example if we update the size of the array the flatten method will not be informed and throw an error:

function setValueV3fArray( gl, v ) {
         // here this.size is in cache and will never change. Maybe we could use v.length?
	const data = flatten( v, this.size, 3 );

	gl.uniform3fv( this.addr, data );

}

If the array length of the uniform value changes this.size seems to not be informed. Is there any reason why we could just not use the value length directly? v.length

const data = flatten( v, v.length, 3 );

This size allocation will stay the same anyway as we need to declare it in the glsl for instance uniform vec3 position[256].

[mrdoob]

Thanks!