message: Overwrite the old session if the new creds are for a different user
  Fixes
diff: @@ -348,15 +348,26 @@ export function setLoggedIn(credentials) {
  * new one in its place. This additionally starts all other react-sdk services
  * which use the new Matrix client.
  *
  + * If the credentials belong to a different user from the session already stored,
  + * the old session will be cleared automatically.
  + *
  * @param {MatrixClientCreds} credentials The credentials to use
  *
  * @returns {Promise} promise which resolves to the new MatrixClient once it has been started
  */
  export function hydrateSession(credentials) {
  - stopMatrixClient();
  + const oldUserId = MatrixClientPeg.get().getUserId();
  +
  + stopMatrixClient(); // unsets MatrixClientPeg.get()
  localStorage.removeItem("mx_soft_logout");
  _isLoggingOut = false;
  - return _doSetLoggedIn(credentials, false);
  +
  + const overwrite = credentials.userId !== oldUserId;
  + if (overwrite) {
  + console.warn("Rehydrating the user's session with a different user's - clearing all data");
  + }
  +
  + return _doSetLoggedIn(credentials, overwrite);
  }
  /**
  