Fix python 3.8 compatibility.

This interferes with backporting and isn't necessary.

Author: mtwebster

usr/lib/webapp-manager/common.py

@@ -169,7 +169,7 @@ def get_webapps(self):
         return webapps
 
     @staticmethod
-    def get_supported_browsers() -> list[Browser]:
+    def get_supported_browsers():
         # type, name, exec, test
         return [Browser(BROWSER_TYPE_FIREFOX, "Firefox", "firefox", "/usr/bin/firefox"),
                 Browser(BROWSER_TYPE_FIREFOX, "Firefox Developer Edition", "firefox-developer-edition", "/usr/bin/firefox-developer-edition"),