txnprovider/shutter: fix block tracker, rpc subscription local notifier

[taratorio]

fixes:

[WARN] [02-26|21:59:15.010] Failed to build a block                  err="[3/4 MiningExecution] issue while waiting for parent block 14520965: context deadline exceeded"

and

[EROR] [02-27|19:45:55.076] catch panic                              err="can't Notify before subscription is created" stack="[log_panic.go:41 panic.go:785 subscription.go:137 eth_filters.go:289 asm_amd64.s:1700]