crypto: Only send cancellations to other devices if we're the requester

matrix_sdk_crypto/src/verification/requests.rs

@@ -579,6 +579,7 @@ impl VerificationRequest {
             let mut inner = self.inner.lock().unwrap();
             inner.cancel(false, content.cancel_code());
 
+            if self.we_started() {
                 if let Some(request) =
                     self.cancel_for_other_devices(content.cancel_code().to_owned(), None)
                 {
@@ -586,6 +587,7 @@ impl VerificationRequest {
                 }
             }
         }
+    }
 
     /// Transition from this verification request into a SAS verification flow.
     pub async fn start_sas(