test/device_information_service_server: update tests

gatt-service/device_information_service_server: check NULL strings

test/gatt_client: add tests

test/gatt_client: extend mock

hci: add hci_get_stack for testing

hci: use assert in hci_number_free_acl_slots_for_connection_type

hci: update state before sending hci command

avdtp_util: fix array size

att_server: fix signed vs. unsigned warnings

att_db: fix signed vs. unsigned warnings

sm: fix unused warning

3rdparty/hxcmod: rename channel into hxcmod_channel_t

btstack_ring_buffer: remove duplicate definition

hcxmod: fix shadow warning, rename sample into a_sample

bluetooth: mark status and att error codes as unsigned

hci: fix warnings

sm: fix unused warnings

tool/metrics: list max values for deviations

sm: extract sm_pdu_handler_pairing_public_key

gatt-service/ancs-client: extract ancs_client_handle_gatt_client_event_in_w4_service_result

att_db_util: Add API to specify next attribute handle. (#647)

Co-authored-by: Alex McHugh <[email protected]>

avdtp_util: move drc field at the end of AVDTP MPEG AAC events definition

btstack_defines: move drc field at the end of AVDTP MPEG AAC events definition and extend corresponding A2DP events with the same field

avdp: use enum type for block lenght and subbands in avdtp_configuration_sbc_t

avdtp_util: fix SBC block length and subbands validation