Bluetooth: Controller: Fix stuck forced continuation under throughput

Fix stuck forced continuation of connection event under high
throughput scenario. At near supervision timeout the force
flag is set, but in the next connection event if full
connection interval is used for data transmission and a
subsequent request to abort happens it was not honoured
causing the tx-rx chain to keep continuing until supervision
timeout.

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