[BREAKING] Remove NimBLEAddress type default value.

When constructing a NimBLEAddress via string or other non `ble_addr_t` parameters it is important that the address type be specified.
This will help prevent issues where applications are not able to connect or identify scanned devices when comparing their addresses.

src/NimBLEDevice.cpp

@@ -614,18 +614,14 @@ bool NimBLEDevice::isBonded(const NimBLEAddress& address) {
 /**
  * @brief Get the address of a bonded peer device by index.
  * @param [in] index The index to retrieve the peer address of.
- * @returns NimBLEAddress of the found bonded peer or nullptr if not found.
+ * @returns NimBLEAddress of the found bonded peer or null address if not found.
  */
 NimBLEAddress NimBLEDevice::getBondedAddress(int index) {
     ble_addr_t peer_id_addrs[MYNEWT_VAL(BLE_STORE_MAX_BONDS)];
     int        num_peers, rc;
     rc = ble_store_util_bonded_peers(&peer_id_addrs[0], &num_peers, MYNEWT_VAL(BLE_STORE_MAX_BONDS));
-    if (rc != 0) {
-        return nullptr;
-    }
-
-    if (index > num_peers || index < 0) {
-        return nullptr;
+    if (rc != 0 || index > num_peers || index < 0) {
+        return NimBLEAddress{};
     }
 
     return NimBLEAddress(peer_id_addrs[index]);
@@ -704,12 +700,12 @@ size_t NimBLEDevice::getWhiteListCount() {
 /**
  * @brief Gets the address at the vector index.
  * @param [in] index The vector index to retrieve the address from.
- * @returns The NimBLEAddress at the whitelist index or nullptr if not found.
+ * @returns The NimBLEAddress at the whitelist index or null address if not found.
  */
 NimBLEAddress NimBLEDevice::getWhiteListAddress(size_t index) {
     if (index > m_whiteList.size()) {
         NIMBLE_LOGE(LOG_TAG, "Invalid index; %u", index);
-        return nullptr;
+        return NimBLEAddress{};
     }
 
     return m_whiteList[index];