### Godot version

v4.2.beta1.official [b1371806a]

### System information

Godot v4.2.beta1 - macOS 12.7.0 - Vulkan (Forward+) - dedicated AMD Radeon HD - FirePro D300 - Intel(R) Xeon(R) CPU E5-1620 v2 @ 3.70GHz (8 Threads)

### Issue description

When creating a plugin with a dot in the name in the project settings and leaving "Script Name" empty fails. Also, when a plugin folder is added via file system which contains a dot, information for that plugin cannot be be updated in the project settings.

Will be solved by: https://github.com/godotengine/godot/pull/83329

### Steps to reproduce

Create new plugin:

- Open project settings
- Click on "Create New Plugin" in the "Plugin" tab
- Choose a name with a dot in it (e.g., "my.plugin") and leave "Script Name" empty
- Create
- It will fail to create the plugin script

Update existing plugin:

- Add a plugin directory with a dot in the folder name (e.g., "my.plugin") in the file system
- Open project settings
- Click on the edit button in the "Plugin" tab for that plugin
- Change "Author" to some name
- Update
- Author was not changed in the table or in "plugin.cfg"

### Minimal reproduction project

[plugin_config_dialog.zip](https://github.com/godotengine/godot/files/12905755/plugin_config_dialog.zip)

ADD_SIGNAL(MethodInfo("plugin_ready", PropertyInfo(Variant::STRING, "script_path", PROPERTY_HINT_NONE, ""), PropertyInfo(Variant::STRING, "activate_name")));
}
PluginConfigDialog::PluginConfigDialog() {
	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(2);
	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_edit = memnew(LineEdit);
	name_edit->set_placeholder("MyPlugin");
	name_edit->set_tooltip_text(TTR("Required. This name will be displayed in the list of plugins."));
	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);
	subfolder_edit = memnew(LineEdit);