crypto: Remove verification objects that are done or canceled.

matrix_sdk_crypto/src/machine.rs

@@ -1094,6 +1094,8 @@ impl OlmMachine {
     /// * `response` - The sync latest sync response.
     #[instrument(skip(response))]
     pub async fn receive_sync_response(&mut self, response: &mut SyncResponse) {
+        self.verification_machine.garbage_collect();
+
         let one_time_key_count = response
             .device_one_time_keys_count
             .get(&keys::KeyAlgorithm::SignedCurve25519);

matrix_sdk_crypto/src/verification/machine.rs

@@ -81,6 +81,11 @@ impl VerificationMachine {
             .collect()
     }
 
+    pub fn garbage_collect(&self) {
+        self.verifications
+            .retain(|_, s| !(s.is_canceled() || s.is_done()));
+    }
+
     pub async fn receive_event(
         &self,
         event: &mut AnyToDeviceEvent,