Fix Proton version detection when using a different default Proton verion (Such as Proton-GE) (SubnauticaNitrox#2727)

Author: BeefyAndTheDucks

Nitrox.Model/Platforms/Store/Steam.cs

@@ -445,6 +445,14 @@ static List<string> GetAllLibraryPaths(string steamPath)
                     {
                         return appIdMatch.Groups[1].Value;
                     }
+                    
+                    const string defaultPattern = @"""0""[^{]*\{[^}]*""name""\s*""([^""]+)""";
+                    Match defaultMatch = Regex.Match(compatToolMapping, defaultPattern);
+                    
+                    if (defaultMatch.Success)
+                    {
+                        return defaultMatch.Groups[1].Value;
+                    }
                 }
 
                 return null;