### Godot version

4.0.beta13 (caacade56)

### System information

Windows 10

### Issue description

Seems like this was missed in #62011 and #70540. `@export_multiline` should also support the PackedStringArray datatype on top of Array[String] and Dictionary, but it doesn't, instead giving the error `"@export_multiline" annotation requires a variable of type "String" but type "PackedStringArray" was given instead.`

### Steps to reproduce

Create a PackedStringArray with the `@export_multiline` annotation.
```gdscript
@export_multiline var npc_dialog: PackedStringArray
```

### Minimal reproduction project

N/A
update_extents(assignment);
	make_completion_context(COMPLETION_ASSIGN, assignment);
#ifdef DEBUG_ENABLED
	bool has_operator = true;
#endif
	switch (previous.type) {
		case GDScriptTokenizer::Token::EQUAL:
			assignment->operation = AssignmentNode::OP_NONE;
			assignment->variant_op = Variant::OP_MAX;
#ifdef DEBUG_ENABLED
			has_operator = false;
#endif
			break;
		case GDScriptTokenizer::Token::PLUS_EQUAL:
			assignment->operation = AssignmentNode::OP_ADDITION;
			assignment->variant_op = Variant::OP_ADD;
			break;
		case GDScriptTokenizer::Token::MINUS_EQUAL:
			assignment->operation = AssignmentNode::OP_SUBTRACTION;
			assignment->variant_op = Variant::OP_SUBTRACT;
			break;
		case GDScriptTokenizer::Token::STAR_EQUAL:
			assignment->operation = AssignmentNode::OP_MULTIPLICATION;
			assignment->variant_op = Variant::OP_MULTIPLY;
			break;
		case GDScriptTokenizer::Token::STAR_STAR_EQUAL:
			assignment->operation = AssignmentNode::OP_POWER;
			assignment->variant_op = Variant::OP_POWER;
			break;
		case GDScriptTokenizer::Token::SLASH_EQUAL: