Refine query selector to highlight unexpected query keys

Previously, there was a catch-all case in RootQuerySelector which would accept any key with type "any". This still allows nice IDE typehints, but can lead to bugs where the incorrect key is used for a filter with no warning that the key is clearly wrong.

With this PR, only keys that contain a "." are unsafely typed as any, which should reduce the blast radius of the hacky types dramatically.

types/query.d.ts

@@ -115,8 +115,9 @@ declare module 'mongoose' {
     /** @see https://www.mongodb.com/docs/manual/reference/operator/query/comment/#op._S_comment */
     $comment?: string;
     // we could not find a proper TypeScript generic to support nested queries e.g. 'user.friends.name'
-    // this will mark all unrecognized properties as any (including nested queries)
-    [key: string]: any;
+    // this will mark all unrecognized properties as any (including nested queries) only if
+    // they include a "." (to avoid generically allowing any unexpected keys)
+    [nestedSelector: `${string}.${string}`]: any;
   };
 
   interface QueryTimestampsConfig {