### Tested versions

See "System information" below.

### System information

Godot v4.1.4.rc (2d3b2abcf) - Windows 10.0.19045 - Vulkan (Compatibility) - NVIDIA GeForce GTX 970 (NVIDIA; 31.0.15.2698) - Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz (8 Threads)

### Issue description

POT generation ignores tr() expression in dictionaries:
```python
var strDeclarer = { 'N':tr("North"), 'E':tr("East"), 'S':tr("South"), 'W':tr("West") }[declarer]
var strVulnerable = { 0:tr("none"), 1:tr("both"), 2:tr("NS"), 3:tr("EW") }[vulnerable]
```
Strings as tr() parameters do not show up in the POT file.

### Steps to reproduce

FYI: [Creating the PO template - Automatic generation using the editor](https://docs.godotengine.org/en/stable/tutorials/i18n/localization_using_gettext.html#automatic-generation-using-the-editor)

### Minimal reproduction project (MRP)

N/A
ERR_FAIL_NULL_V(p_expression, false);
	return p_expression->is_constant && (p_expression->reduced_value.get_type() == Variant::STRING || p_expression->reduced_value.get_type() == Variant::STRING_NAME);
}
void GDScriptEditorTranslationParserPlugin::_traverse_class(const GDScriptParser::ClassNode *p_class) {
	for (int i = 0; i < p_class->members.size(); i++) {
		const GDScriptParser::ClassNode::Member &m = p_class->members[i];
		
		switch (m.type) {
			case GDScriptParser::ClassNode::Member::CLASS:
				_traverse_class(m.m_class);
				break;
			case GDScriptParser::ClassNode::Member::FUNCTION:
				_traverse_function(m.function);
				break;
			case GDScriptParser::ClassNode::Member::VARIABLE:
				_read_variable(m.variable);
				break;
			default:
				break;
		}
	}
}
void GDScriptEditorTranslationParserPlugin::_traverse_function(const GDScriptParser::FunctionNode *p_func) {
	_traverse_block(p_func->body);
}
void GDScriptEditorTranslationParserPlugin::_read_variable(const GDScriptParser::VariableNode *p_var) {