### Godot version

4.2 f7bc653

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

`get_method()`:
```
Returns the name of the method represented by this Callable. If the callable is a lambda function, returns the function's name
```
However calling it on a named lambda results in
```
Can't get method on CallableCustom "test(lambda)".
```
(ironically the error even contains the function's name...)

`get_method()` in GDScriptLambdaCallable is likely unimplemented or is wrong. It should work for named lambdas.

### Steps to reproduce

```GDScript
var fun = func test(): pass
print(fun.get_method())
```

### Minimal reproduction project

N/A
#include "gdscript_lambda_callable.h"
#include "gdscript.h"
#include "core/templates/hashfuncs.h"
bool GDScriptLambdaCallable::compare_equal(const CallableCustom *p_a, const CallableCustom *p_b) {
	
	return p_a == p_b;
}
bool GDScriptLambdaCallable::compare_less(const CallableCustom *p_a, const CallableCustom *p_b) {
	
	return p_a < p_b;
}
uint32_t GDScriptLambdaCallable::hash() const {
	return h;
}
String GDScriptLambdaCallable::get_as_text() const {
	if (function->get_name() != StringName()) {
		return function->get_name().operator String() + "(lambda)";
	}
	return "(anonymous lambda)";
}
CallableCustom::CompareEqualFunc GDScriptLambdaCallable::get_compare_equal_func() const {