### Godot version

v4.1.dev.custom_build.a7276f1ce

### System information

Win10, AMD 2600, GeForce GTX 1060, Vulkan API 1.3.205

### Issue description

I can't get correct color data from an array of source_color type.
The color data is saved as **Color** in the file:
`shader_parameter/palette = [Color (1, 0, 0, 1), Color (0, 1, 0, 1), Color (0, 0, 1, 1)]`
Shouldn't it be saved as PackedColorArray?


### Steps to reproduce

1.Declare an array of source_color type.
2.Set colors.

### Minimal reproduction project

[shadertest.zip](https://github.com/godotengine/godot/files/11246504/shadertest.zip)

code += "	if (!particles_anim_loop) {\n";
			code += "		particle_frame = clamp(particle_frame, 0.0, particle_total_frames - 1.0);\n";
			code += "	} else {\n";
			code += "		particle_frame = mod(particle_frame, particle_total_frames);\n";
			code += "	}\n";
			code += "	UV /= vec2(h_frames, v_frames);\n";
			code += "	UV += vec2(mod(particle_frame, h_frames) / h_frames, floor((particle_frame + 0.5) / h_frames) / v_frames);\n";
		} break;
		case BILLBOARD_MAX:
			break; 
	}
	if (flags[FLAG_FIXED_SIZE]) {
		code += "	if (PROJECTION_MATRIX[3][3] != 0.0) {\n";
		
		
		code += "		float h = abs(1.0 / (2.0 * PROJECTION_MATRIX[1][1]));\n";
		code += "		float sc = (h * 2.0); //consistent with Y-fov\n";
		code += "		MODELVIEW_MATRIX[0]*=sc;\n";
		code += "		MODELVIEW_MATRIX[1]*=sc;\n";
		code += "		MODELVIEW_MATRIX[2]*=sc;\n";
		code += "	} else {\n";
		
		code += "		float sc = -(MODELVIEW_MATRIX)[3].z;\n";
		code += "		MODELVIEW_MATRIX[0]*=sc;\n";
		code += "		MODELVIEW_MATRIX[1]*=sc;\n";
		code += "		MODELVIEW_MATRIX[2]*=sc;\n";
		code += "	}\n";
	}
	if (detail_uv == DETAIL_UV_2 && !flags[FLAG_UV2_USE_TRIPLANAR]) {
		code += "	UV2=UV2*uv2_scale.xy+uv2_offset.xy;\n";