Reverting colors in a spatial shader with a custom inspector, reverts the colors incorrectly

[Arnklit]

Godot version:
3.2.3.Stable

OS/device including version:
NA

Issue description:
When implementing a custom inspector by parsing values from a shader and reverting them, the reverted colors end up too bright.

Steps to reproduce:
Open up the attached project and open the "spatial_example.tscn" and try setting the colors and reverting them.
Note: This is not an issue when using a canvas_item shader. There is an "canvas_item_example.tscn" included in the project, that is set up the same way but with a canvas_item shader that shows no issue.

Minimal reproduction project:
color_revert.zip

[Arnklit]

I've been looking for a workaround for this and found another way of showing the issue that might be easier to troubleshoot.

set_shader_param("color_parameter", null)

Will cause the same issue, with "resetting" to this incorrect brighter value.

[Calinou]

This is likely to be a sRGB conversion issue, but the issue may be in the renderer instead of the editor inspector.

[Arnklit]

I've been running into more issues using custom inspectors for materials. I assume it's all connected. For example in this case using a mat4 uniform to tranfer data, the revert is also changing values in unexpected ways inside the shader if you use a custom inspector, but not if you use the ShaderMaterial inspector.

The uniform being serialised above just looks like this in the shader:

uniform mat4 colors = mat4(vec4(0.1, 0.4, 0.7, 1.0), vec4(0.2, 0.5, 0.8, 1.1), vec4(0.3, 0.6, 0.9, 1.2), vec4(0.0));

[akien-mga]

CC @godotengine/rendering