pallet-bounties: allow bounties to never expire #17199

Job	Run time
isdraft / isdraft	1s
preflight / preflight	9s
preflight / ci-versions	1m 25s
build-linux-stable	5m 52s
build-linux-stable-cumulus	5m 50s
build-test-parachain	5m 1s
build-linux-substrate	5m 18s
build-malus	4m 37s
build-test-collators	5m 3s
prepare-bridges-zombienet-artifacts	3m 55s
prepare-cumulus-zombienet-artifacts	2m 47s
prepare-polkadot-zombienet-artifacts	3m 30s
build-push-image-test-parachain	21s
build-push-image-colander	1s
build-push-image-substrate-pr	1s
build-push-image-polkadot-debug	1s
build-push-image-malus	1s
build-push-image-polkadot-parachain-debug	1s
build-push-image-bridges-zombienet-tests	1s
	43m 55s

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