Unwrap payload bid (#14035)

* engine GetPayload returns entire response

* deprecate PayloadValueTo(Gwei|Wei)

* return entire bid from builder getter

* get bid value from api bid (not ExecutionData)

* plumb bid and bundle through BuildBlockParallel

* rm ValueInGwei

* removing wei/gwei fields from the payload wrappers

* commentary around the little-endian situation

* finish the job in BuildBlockParallel

* light self-review cleanup

* fix spectest mock

* restore engine timeout

* lint fixes

* de-duplicate imports

* remove errant comment

* James feedback

---------

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

api/client/builder/client.go

@@ -330,7 +330,7 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 	if err != nil {
 		return nil, nil, err
 	}
-	ed, err := blocks.NewWrappedExecutionData(pb, nil)
+	ed, err := blocks.NewWrappedExecutionData(pb)
 	if err != nil {
 		return nil, nil, err
 	}