Revert "feat(sources): X-Account-Verwaltung im Verwaltungsportal"

This reverts commit bd476edb13.

src/source_meta.py

@@ -38,7 +38,6 @@ SOURCE_CATEGORIES: list[CategoryEntry] = [
     {"key": "russische-staatspropaganda",  "label": "Russische Staatspropaganda"},
     {"key": "russische-opposition",        "label": "Russische Opposition / Exilmedien"},
     {"key": "syrien-nahost",               "label": "Syrien / Nahost"},
-    {"key": "x",                           "label": "X-Recherche"},
 ]
 
 
@@ -48,7 +47,6 @@ SOURCE_TYPES: list[TypeEntry] = [
     {"key": "telegram_channel", "label": "Telegram-Kanal"},
     {"key": "podcast_feed",     "label": "Podcast-Feed"},
     {"key": "excluded",         "label": "Ausgeschlossen"},
-    {"key": "x_account",        "label": "X-Account"},
 ]