Revert "Attempt bumping `inspectcode` to fix remaining inspection"

This reverts commit e018a6d6a5.

.config/dotnet-tools.json

@@ -9,7 +9,7 @@
       ]
     },
     "jetbrains.resharper.globaltools": {
-      "version": "2021.2.2",
+      "version": "2020.3.2",
       "commands": [
         "jb"
       ]

osu.Game/Stores/RealmRulesetStore.cs

@@ -106,8 +106,9 @@ private void addMissingRulesets()
                 var rulesets = realm.All<RealmRuleset>();
 
                 List<Ruleset> instances = loadedAssemblies.Values
-                                                          .Select(Activator.CreateInstance)
-                                                          .OfType<Ruleset>()
+                                                          .Select(r => Activator.CreateInstance(r) as Ruleset)
+                                                          .Where(r => r != null)
+                                                          .Cast<Ruleset>()
                                                           .ToList();
 
                 // add all legacy rulesets first to ensure they have exclusive choice of primary key.