Bluetooth: Audio: Shell: Improve printing of incoming audio

Instead of printing every audio packet (typically
arriving every 7.5 or 10ms), we now only print every 100th.

Ideally we would add support for changing the number of
"skippe" audio packets at runtime in a shell command, but
that will be postponed.

Ideally we would also have a rx_cnt per stream, but that will
also be postponed to the future, and should be fixed with e.g.
the sequence number (seq_num) as well.

Finally this commit also adds a verification if the currently
incoming data packet contains the same ts or seq_num of the
previous one, and print if it does, as this indicates that
we are receiving some invalid data.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>