chore: add Amazon Pay feature flag #15512

Job	Run time
generate-matrix	6s
WC - 9.9.5 \| PHP - 8.3 \| wcpay - shopper	25m 23s
WC - 9.9.5 \| PHP - 8.3 \| wcpay - merchant	15m 53s
WC - latest \| PHP - 8.3 \| wcpay - merchant	15m 35s
WC - 9.9.5 \| PHP - 8.3 \| subscriptions - shopper	7m 14s
WC - 9.9.5 \| PHP - 8.3 \| blocks - shopper	7m 22s
WC - 9.9.5 \| PHP - 8.3 \| subscriptions - merchant	5m 36s
WC - latest \| PHP - 8.3 \| wcpay - shopper	25m 27s
WC - latest \| PHP - 8.3 \| subscriptions - merchant	5m 39s
WC - latest \| PHP - 8.3 \| blocks - shopper	5m 45s
WC - latest \| PHP - 8.3 \| subscriptions - shopper	7m 24s
generate-matrix	6s
WC - 9.9.5 \| PHP - 8.3 \| wcpay - merchant	15m 53s
WC - 9.9.5 \| PHP - 8.3 \| subscriptions - shopper	7m 14s
WC - 9.9.5 \| PHP - 8.3 \| wcpay - shopper	25m 23s
WC - 9.9.5 \| PHP - 8.3 \| subscriptions - merchant	5m 36s
WC - latest \| PHP - 8.3 \| blocks - shopper	6m 54s
WC - latest \| PHP - 8.3 \| subscriptions - shopper	7m 24s
WC - latest \| PHP - 8.3 \| wcpay - shopper	25m 27s
WC - latest \| PHP - 8.3 \| wcpay - merchant	15m 35s
WC - 9.9.5 \| PHP - 8.3 \| blocks - shopper	7m 22s
WC - latest \| PHP - 8.3 \| subscriptions - merchant	5m 39s
	4h 3m 57s

Provide feedback