Remove address from whitelist if the procedure fails.

This prevents a situation where the whitelist contains the address but the procedure errors and the address cannot be added again.

src/NimBLEDevice.cpp

@@ -678,6 +678,7 @@ bool NimBLEDevice::whiteListAdd(const NimBLEAddress & address) {
     int rc = ble_gap_wl_set(&wlVec[0], wlVec.size());
     if (rc != 0) {
         NIMBLE_LOGE(LOG_TAG, "Failed adding to whitelist rc=%d", rc);
+        m_whiteList.pop_back();
         return false;
     }