only use legacy 3-digit season/episode guess when no better signal exists

plex-library-tool.py

@@ -149,6 +149,7 @@ def parse_season_episode(filename):
             episode = int(m.group(2))
             return season, episode, marker
 
+    if parse_season_only(filename) is None and parse_episode_only(filename) is None:
         m = LEGACY_SEE_PATTERN.search(filename)
         if m:
             season = int(m.group(1))