### 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)

grid->add_child(version_lb);
	version_edit = memnew(LineEdit);
	version_edit->set_tooltip_text(TTR("Optional. A human-readable version identifier used for informational purposes only."));
	version_edit->set_placeholder("1.0");
	version_edit->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	grid->add_child(version_edit);
	
	Label *script_option_lb = memnew(Label);
	script_option_lb->set_text(TTR("Language:"));
	script_option_lb->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_RIGHT);
	grid->add_child(script_option_lb);
	script_option_edit = memnew(OptionButton);
	script_option_edit->set_tooltip_text(TTR("Required. The scripting language to use for the script.\nNote that a plugin may use several languages at once by adding more scripts to the plugin."));
	int default_lang = 0;
	for (int i = 0; i < ScriptServer::get_language_count(); i++) {
		ScriptLanguage *lang = ScriptServer::get_language(i);
		script_option_edit->add_item(lang->get_name());
		if (lang->get_name() == "GDScript") {
			default_lang = i;
		}
	}
	script_option_edit->select(default_lang);
	grid->add_child(script_option_edit);
	
	Label *script_lb = memnew(Label);
	script_lb->set_text(TTR("Script Name:"));
	script_lb->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_RIGHT);
	grid->add_child(script_lb);
	script_edit = memnew(LineEdit);
	script_edit->set_tooltip_text(TTR("Optional. The path to the script (relative to the add-on folder). If left empty, will default to \"plugin.gd\"."));