Define the UCI packets for Data Tx notifications

Define the UCI packets for DATA_CREDIT_NTF and DATA_TRANSFER_STATUS_NTF,
both of which are notifications received by the host device, when it
sends a UCI data packet to the UWBS.

Bug: 261886903
Test: atest libuwb_core_test libuwb_uci_packet_tests
Change-Id: Idf28355826375052514f7dedd0b8e76b3b8d2352