Merge pull request atomvm#755 from bettio/handle-ns-not-found

ESP32/NVS: return `namespace_not_found` as `undefined` in get function

Fixes `nvs_get_binary/2` so it can work on devices with a completely erased NVS
area.

namespace not found is quite common in a newly flash device, for consistency
reasons it should be returned as undefined.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

libs/eavmlib/src/esp.erl

@@ -180,6 +180,7 @@ nvs_get_binary(Namespace, Key) when is_atom(Namespace) andalso is_atom(Key) ->
     case esp:nvs_fetch_binary(Namespace, Key) of
         {ok, Result} -> Result;
         {error, not_found} -> undefined;
+        {error, namespace_not_found} -> undefined;
         {error, OtherError} -> throw(OtherError)
     end.