[cookies] Update regex for Firefox containers JSON version 4

Co-authored-by: bashonly <88596187+bashonly@users.noreply.github.com>

yt_dlp/cookies.py

@@ -146,7 +146,7 @@ def _extract_firefox_cookies(profile, container, logger):
             identities = json.load(containers).get('identities', [])
         container_id = next((context.get('userContextId') for context in identities if container in (
             context.get('name'),
-            try_call(lambda: re.fullmatch(r'userContext([^\.]+)\.label', context['l10nID']).group()),
+            try_call(lambda: re.fullmatch(r'userContext([^.]+)\.label', context['l10nID']).group()),
             try_call(lambda: re.fullmatch(r'user-context-(.+)', context['l10nId']).group())
         )), None)
         if not isinstance(container_id, int):