### 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)

case TYPE_BVEC4:
									member_type = TYPE_BOOL;
									break;
								case TYPE_VEC4:
									member_type = TYPE_FLOAT;
									break;
								case TYPE_IVEC4:
									member_type = TYPE_INT;
									break;
								case TYPE_UVEC4:
									member_type = TYPE_UINT;
									break;
								case TYPE_MAT4:
									member_type = TYPE_VEC4;
									break;
								default:
									break;
							}
							break;
						default: {
							_set_error(vformat(RTR("An object of type '%s' can't be indexed."), (expr->get_datatype() == TYPE_STRUCT ? expr->get_datatype_name() : get_datatype_name(expr->get_datatype()))));
							return nullptr;
						}
					}
				}
				OperatorNode *op = alloc_node<OperatorNode>();
				op->op = OP_INDEX;
				op->return_cache = member_type;
				op->struct_name = member_struct_name;
				op->arguments.push_back(expr);