[webkitcorepy] Exit AutoInstall.install when disabled

https://bugs.webkit.org/show_bug.cgi?id=270920
rdar://124542328

Reviewed by Elliott Williams.

AutoInstall.install will fail if the autoinstaller is disabled.
Programs shouldn't call AutoInstall.install if the autoinstaller
is disabled, but the program may still complete, so we should
just print an error message.

* Tools/Scripts/libraries/webkitcorepy/webkitcorepy/autoinstall.py:
(AutoInstall.install): Exit and print error if AutoInstall is disabled.

Canonical link: https://commits.webkit.org/276051@main

Tools/Scripts/libraries/webkitcorepy/webkitcorepy/autoinstall.py

@@ -668,6 +668,9 @@ def register(cls, package, local=False):
 
     @classmethod
     def install(cls, package):
+        if not cls.enabled():
+            sys.stderr.write("Autoinstaller disabled, but 'install' called\n")
+            return None
         if isinstance(package, str):
             # we want this to throw if it hasn't been previously registered; in the case
             # that this is being called from cls.find_module it should always exist