Remove strict fee recipient (#3552)

## Issue Addressed

Resolves: #3550

Remove the `--strict-fee-recipient` flag. It will cause missed proposals prior to the bellatrix transition.

Co-authored-by: realbigsean <sean@sigmaprime.io>

validator_client/src/lib.rs

@@ -420,7 +420,6 @@ impl<T: EthSpec> ProductionValidatorClient<T> {
             .runtime_context(context.service_context("block".into()))
             .graffiti(config.graffiti)
             .graffiti_file(config.graffiti_file.clone())
-            .strict_fee_recipient(config.strict_fee_recipient)
             .build()?;
 
         let attestation_service = AttestationServiceBuilder::new()