remove now unused method

src/crypto/verification/request/VerificationRequest.js

@@ -244,26 +244,6 @@ export default class VerificationRequest extends EventEmitter {
         }
     }
 
-    /**
-     * @returns {Promise} with the verifier once it becomes available.
-     * Can be used after calling `accept` to wait for the other party to start verification.
-     */
-    waitForVerifier() {
-        if (this.verifier) {
-            return Promise.resolve(this.verifier);
-        } else {
-            return new Promise(resolve => {
-                const checkVerifier = () => {
-                    if (this.verifier) {
-                        this.off("change", checkVerifier);
-                        resolve(this.verifier);
-                    }
-                };
-                this.on("change", checkVerifier);
-            });
-        }
-    }
-
     _setPhase(phase, notify = true) {
         this._phase = phase;
         if (notify) {