consensus::valid_header_version() logic incorrect for floonet/user_testing

[antiochp]

consensus::valid_header_version() makes assumptions around the HARD_FORK_INTERVAL.
This is only valid in mainnet.
floonet and user_testing and automated_testing use different HF intervals.

grin/core/src/consensus.rs

Lines 174 to 178 in b570ac9

	/// Check whether the block version is valid at a given height, implements
	/// 6 months interval scheduled hard forks for the first 2 years.
	pub fn valid_header_version(height: u64, version: HeaderVersion) -> bool {
	height < 3 * HARD_FORK_INTERVAL && version == header_version(height)
	}

We should rework valid_header_version() with consistent behavior across all chain types.

height < n * HARD_FORK_INTERVAL will effectively be true for all chain types other than mainnet due to reduced chain height. Logic here is not correct for other chain types.

[antiochp]

As @tromp mentioned in #3334 this just means we have 2 years of blocks at version 4 regardless of chain type.
So lets leave this as-is.

We can test against automatedtesting chain type based on header version once we get to version 4 regardless.

Closing this.