Add name info to EditorAutoloadSettings invalid name message

[ktxyz]

Possibly closes #110258.

Adding direct info about which name caused the error makes sense. Not right after the colon as suggested in the issue since there might be different reasons for Autoload fail. Adding this inside invalid name error seems like a good place, since other cases already include more information:

String error;
if (!_autoload_name_is_valid(name, &error)) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + error);
  return false;
}

if (!FileAccess::exists(p_path)) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + vformat(TTR("%s is an invalid path. File does not exist."), p_path));
  return false;
}

if (!p_path.begins_with("res://")) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + vformat(TTR("%s is an invalid path. Not in resource path (res://)."), p_path));
  return false;
}

Before:

After:

[ktxyz]

I moved the name as prefix to the actual message so it doesn't impact translation in any way, unlike having it as Invalid Name: %s.

[Calinou]

I would expect it to look like this instead:

Can't add Autoload: invalid name.
GlobalTetrahedron: Must not collide with an existing global script class name.

Notice the lowercase "i" for "invalid name", and the fact it's on the same line as the "header" of the error dialog.

[ktxyz]

I would expect it to look like this instead:

Can't add Autoload: invalid name.
GlobalTetrahedron: Must not collide with an existing global script class name.

Notice the lowercase "i" for "invalid name", and the fact it's on the same line as the "header" of the error dialog.

The "header" part only really exists for invalid name and not other options

if (!_autoload_name_is_valid(name, &error)) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + error);
  return false;
}

if (!FileAccess::exists(p_path)) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + vformat(TTR("%s is an invalid path. File does not exist."), p_path));
  return false;
}

if (!p_path.begins_with("res://")) {
  EditorNode::get_singleton()->show_warning(TTR("Can't add Autoload:") + "\n" + vformat(TTR("%s is an invalid path. Not in resource path (res://)."), p_path));
  return false;
}

So this would have us

Can't add Autoload: invalid name.
%s: Must not collide with an existing global script class name.
---
Can't add Autoload:
%s is an invalid path. File does not exist.
---
Can't add Autoload:
%s is an invalid path. Not in resource path (res://).

How about

Can't add Autoload:
%s is an invalid name. Must not collide with an existing global script class name.
---
Can't add Autoload:
%s is an invalid path. File does not exist.
---
Can't add Autoload:
%s is an invalid path. Not in resource path (res://).

This has message formats the same for each case and only requires '%s is an invalid name.' translation.