ACP-226: Add MinDelayExcess to header

[ceyonur]

Why this should be merged

Adds the MinBlockDelayExcess to header and relevant places.

Note: this does not properly handle/enforce the verification + build path yet.

Closes: #1231

How this works

Adds the field to header, runs generate tools.

How this was tested

Added the field to existing tests

Need to be documented?

maybe as a part of bigger ACP-226

Need to update RELEASES.md?

updated

[powerslider]

Shouldn't the header be added in consensus/miner/worker.go as well:

if chainExtra.IsGranite(header.Time) {
        headerExtra := customtypes.GetHeaderExtra(header)
        headerExtra.TimeMilliseconds = &timestampMS

        // Initialize MinBlockDelayExcess so the field is present in post-Granite headers.
        if headerExtra.MinBlockDelayExcess == nil {
	        *headerExtra.MinBlockDelayExcess = 0
        }
}

[ceyonur]

Shouldn't the header be added in consensus/miner/worker.go as well:

if chainExtra.IsGranite(header.Time) {
        headerExtra := customtypes.GetHeaderExtra(header)
        headerExtra.TimeMilliseconds = &timestampMS

        // Initialize MinBlockDelayExcess so the field is present in post-Granite headers.
        if headerExtra.MinBlockDelayExcess == nil {
	        *headerExtra.MinBlockDelayExcess = 0
        }
}

I did not add checks and build path here. This just defines the field and adds to only necessary places to make UT pass. Mainly because we can't properly verify and set it while this PR is still pending ava-labs/avalanchego#4289