### 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)

_set_error(RTR("Only integer expressions are allowed for indexing."));
							return nullptr;
						}
						if (index_expression->type == Node::NODE_TYPE_CONSTANT) {
							ConstantNode *cnode = static_cast<ConstantNode *>(index_expression);
							if (cnode) {
								if (!cnode->values.is_empty()) {
									int value = cnode->values[0].sint;
									if (value < 0 || value >= array_size) {
										_set_error(vformat(RTR("Index [%d] out of range [%d..%d]."), value, 0, array_size - 1));
										return nullptr;
									}
								}
							}
						}
						tk = _get_token();
						if (tk.type != TK_BRACKET_CLOSE) {
							_set_expected_error("]");
							return nullptr;
						}
					} else {
						_set_tkpos(prepos);
					}
					ArrayNode *arrname = alloc_node<ArrayNode>();
					arrname->name = identifier;
					arrname->datatype_cache = data_type;
					arrname->struct_name = struct_name;
					arrname->index_expression = index_expression;
					arrname->call_expression = call_expression;
					arrname->assign_expression = assign_expression;