Bug: Block Validation

[andy-shi88]

Description

In blockMainService:ValidateBlock we still have legacy code that check the block timestamp base on current timestamp. With the new smithing logic we should not need that.

Having the check will break the block validation since ValidateBlock will be used by downloadBlock or processFork and they shouldn't depends on node's current timestamp.

Breakdowns:

• remove the timestamp check based on node's timestamp in ValidateBlock function (also check on spinechain if having similar issue)