Remove deprecated authedRequestWithPrefix and requestWithPrefix

replacing as documented with authedRequest

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/base-apis.js

@@ -475,8 +475,10 @@ MatrixBaseApis.prototype.fetchRelations =
             $relationType: relationType,
             $eventType: eventType,
         });
-    const response = await this._http.authedRequestWithPrefix(
-        undefined, "GET", path, null, null, httpApi.PREFIX_UNSTABLE,
+    const response = await this._http.authedRequest(
+        undefined, "GET", path, null, null, {
+            prefix: httpApi.PREFIX_UNSTABLE,
+        },
     );
     return response;
 };