Core: Add launch function to call launch_subprocess only if multiprocessing is actually necessary (#4237)

* skips opening a subprocess if kivy (and thus the launcher gui) hasn't been loaded so stdin can function as expected on --nogui and similar

* this exists lol

* keep old function around and use new function for CC component

* fix name=None typing

worlds/LauncherComponents.py

@@ -87,7 +87,7 @@ class Component:
 processes = weakref.WeakSet()
 
 
-def launch_subprocess(func: Callable, name: str = None, args: Tuple[str, ...] = ()) -> None:
+def launch_subprocess(func: Callable, name: str | None = None, args: Tuple[str, ...] = ()) -> None:
     global processes
     import multiprocessing
     process = multiprocessing.Process(target=func, name=name, args=args)
@@ -95,6 +95,14 @@ def launch_subprocess(func: Callable, name: str = None, args: Tuple[str, ...] =
     processes.add(process)
 
 
+def launch(func: Callable, name: str | None = None, args: Tuple[str, ...] = ()) -> None:
+    from Utils import is_kivy_running
+    if is_kivy_running():
+        launch_subprocess(func, name, args)
+    else:
+        func(*args)
+
+
 class SuffixIdentifier:
     suffixes: Iterable[str]
 
@@ -111,7 +119,7 @@ class SuffixIdentifier:
 
 def launch_textclient(*args):
     import CommonClient
-    launch_subprocess(CommonClient.run_as_textclient, name="TextClient", args=args)
+    launch(CommonClient.run_as_textclient, name="TextClient", args=args)
 
 
 def _install_apworld(apworld_src: str = "") -> Optional[Tuple[pathlib.Path, pathlib.Path]]: