Effects may not handle changing the shader source filename properties at all

A suspicion that needs to be confirmed first.

Looking at QQuick3DEffect it is unlikely that it supports changing the shader property of a QQuick3DShaderUtilsShader in a QQuick3DShaderUtilsRenderPass. The changes are most likely ignored since once the effect backend node is ready, all changes to properties (except for user properties) are ignored.

To be verified/fixed once QTBUG-104759 is in place.