remove unused draft code

src/matrix/e2ee/megolm/decryption/ISessionSource.ts

@@ -1,26 +0,0 @@
-/*
-Copyright 2021 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-//import type {InboundGroupSession} from "@matrix-org/olm";
-interface InboundGroupSession {}
-
-export interface ISessionSource {
-	deserializeIntoSession(session: InboundGroupSession): void;
-	get roomId(): string;
-    get senderKey(): string;
-    get sessionId(): string;
-    get claimedEd25519Key(): string;
-}