### 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 (!p_op->arguments[1]->is_indexed()) {
				sb = p_op->arguments[1]->get_array_size();
			}
			if (sa != sb) {
				break; 
			}
			DataType na = p_op->arguments[0]->get_datatype();
			DataType nb = p_op->arguments[1]->get_datatype();
			if (na == TYPE_STRUCT || nb == TYPE_STRUCT) {
				valid = p_op->arguments[0]->get_datatype_name() == p_op->arguments[1]->get_datatype_name();
			} else {
				valid = na == nb;
			}
			ret_type = na;
			ret_size = sa;
		} break;
		case OP_ASSIGN_ADD:
		case OP_ASSIGN_SUB:
		case OP_ASSIGN_MUL:
		case OP_ASSIGN_DIV: {
			int sa = 0;
			int sb = 0;
			if (!p_op->arguments[0]->is_indexed()) {
				sa = p_op->arguments[0]->get_array_size();
			}
			if (!p_op->arguments[1]->is_indexed()) {
				sb = p_op->arguments[1]->get_array_size();
			}
			if (sa > 0 || sb > 0) {
				break;