Bluetooth: shell: gatt-write-without-response with repeat

Add a repeat param to gatt-write-without-response so that
it covers what gatt-write-without-response-repeated was
doing. gatt-write-without-response was removed in the
commit 26eae70d.

gatt-write-signed too will have repeat param with this
change.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>