### Godot version

4.0

### System information

Windows 10 x64

### Issue description

We have an established way to inform about invalid input fields: using red/green/yellow labels at the bottom:
![](https://user-images.githubusercontent.com/2223172/235779087-7db4a899-dd41-40c7-8cb3-b295a42eec5e.png)
It's used in Create New Scene dialog, Add Metadata dialog, New Folder dialog, Create Script dialog and probably others.

Meantime the New Plugin dialog (accessible in Project Settings -> Plugins) looks like this:
![image](https://user-images.githubusercontent.com/2223172/235783588-ef5e560c-8620-4017-9b50-86f8477fe40e.png)
Instead of info labels, it uses info icons that show message on hover. This dialog was created before we had an established way of validating input, so it needs updating.

### Steps to reproduce

1. Project
2. Project Settings
3. Plugins
4. Create New Plugin
5. 👀

### Minimal reproduction project

N/A
get_ok_button()->set_disabled(true);
	set_hide_on_ok(true);
	VBoxContainer *vbox = memnew(VBoxContainer);
	vbox->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	vbox->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	add_child(vbox);
	GridContainer *grid = memnew(GridContainer);
	grid->set_columns(3);
	grid->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	vbox->add_child(grid);
	
	Label *name_lb = memnew(Label);
	name_lb->set_text(TTR("Plugin Name:"));
	name_lb->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_RIGHT);
	grid->add_child(name_lb);
	name_validation = memnew(TextureRect);
	name_validation->set_v_size_flags(Control::SIZE_SHRINK_CENTER);
	grid->add_child(name_validation);
	name_edit = memnew(LineEdit);
	name_edit->connect("text_changed", callable_mp(this, &PluginConfigDialog::_on_required_text_changed));
	name_edit->set_placeholder("MyPlugin");
	name_edit->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	grid->add_child(name_edit);
	
	Label *subfolder_lb = memnew(Label);
	subfolder_lb->set_text(TTR("Subfolder:"));
	subfolder_lb->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_RIGHT);
	grid->add_child(subfolder_lb);