Alchemy websocket for aggregator service

[PowVT]

Currently, it is possible to use an Alchemy websocket in the config for the operator. But when you try to use an Alchemy websocket in the Aggregator iwth debug logs, the service stalls after this log:

2024-07-23T12:59:20.106-0400	DEBUG	operatorsinfo/operatorsinfo_inmemory.go:83	Subscribing to new pubkey registration events on blsApkRegistry contract	{"service": "OperatorPubkeysServiceInMemory"}