### 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)

op->arguments.push_back(index);
				expr = op;
				tk = _get_token();
				if (tk.type != TK_BRACKET_CLOSE) {
					_set_expected_error("]");
					return nullptr;
				}
			} else if (tk.type == TK_OP_INCREMENT || tk.type == TK_OP_DECREMENT) {
				OperatorNode *op = alloc_node<OperatorNode>();
				op->op = tk.type == TK_OP_DECREMENT ? OP_POST_DECREMENT : OP_POST_INCREMENT;
				op->arguments.push_back(expr);
				if (!_validate_operator(op, &op->return_cache, &op->return_array_size)) {
					_set_error(RTR("Invalid base type for increment/decrement operator."));
					return nullptr;
				}
				if (!_validate_assign(expr, p_function_info)) {
					_set_error(RTR("Invalid use of increment/decrement operator in a constant expression."));
					return nullptr;
				}
				expr = op;
			} else {
				_set_tkpos(pos2);
				break;
			}
		}
		Expression e;
		e.is_op = false;
		e.node = expr;
		expression.push_back(e);
		pos = _get_tkpos();