Bluetooth: GATT: Fix not parsing result of Read by Type

When using the procedure Read By Type the response may contain multiple
instances so it needs to be parsed properly. When dealing with long
values only the beggining will be read, for the remaining bytes the
application should issue another bt_gatt_read with offset so Read Blob
procedure is used as recommended by the spec:

BLUETOOTH CORE SPECIFICATION Version 5.1 | Vol 3, Part F page 2312:

The Read Blob Request would be used to read the remaining octets of a
long attribute value.

Fixes #16107

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>