NimBLEDevice::onSync should call taskYIELD() before returning.

This change is needed to allow any tasks that were stopped during a host reset to finish
before resuming from the re-sync. This would occasionally result in a LoadStoreError exception
if not done.

src/NimBLEDevice.cpp

@@ -446,6 +446,10 @@ void NimBLEDevice::stopAdvertising() {
     int rc = ble_hs_util_ensure_addr(0);
     assert(rc == 0);
 
+    // Yield for houskeeping before returning to operations.
+    // Occasionally triggers exception without.
+    taskYIELD();
+
     m_synced = true;
 
     if(initialized) {