Fix `zombienet-bridges-0001-asset-transfer-works` (#6175)

Closes https://github.com/paritytech/polkadot-sdk/issues/6161

Westend BridgeHub freezes for a while at block 3 and if we try to init
the bridge and fund the accounts during that time, it fails. So we wait
untill all the parachains produced at least 10 blocks, in order to make
sure that they work reliably.