### 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)

}
									if (!valid) {
										_set_error(vformat(RTR("Argument %d of function '%s' can only take a local variable, array, or member."), arg_idx + 1, String(name)));
										return false;
									}
								}
							}
						}
						outarg_idx++;
					}
					
					for (int i = 0; i < argcount; i++) {
						if (get_scalar_type(args[i]) != args[i] || args[i] == builtin_func_defs[idx].args[i] || p_func->arguments[i + 1]->type != Node::NODE_TYPE_CONSTANT) {
							
							continue;
						}
						
						ConstantNode *constant = static_cast<ConstantNode *>(p_func->arguments[i + 1]);
						ConstantNode *conversion = alloc_node<ConstantNode>();
						conversion->datatype = builtin_func_defs[idx].args[i];
						conversion->values.resize(1);
						convert_constant(constant, builtin_func_defs[idx].args[i], conversion->values.ptrw());
						p_func->arguments.write[i + 1] = conversion;
					}
					if (r_ret_type) {
						*r_ret_type = builtin_func_defs[idx].rettype;
					}
					return true;
				}
			}