The default value of the uniform type "color" can lead to suspected scene when the user has not uploaded a value.

[Sway007]

Is your feature request related to a problem? Please describe.
The current default value for not uploaded color uniform is (0,0,0,0)，which cause the entites and material inspector in editor be totally transparent, which is like some bug.

Describe the solution you'd like
Change the default value for not uploaded color uniform to (0,0,0,1) or any reasonable value which get rid of this buggy phenomenon

Additional context
Material with not uploaded color uniform often present when user delete a color type property from the Editor module of ShaderLab, related issue galacean/editor#3088