Use fieldparams for BLS public key (#10042)

* Use fieldparams for pubkey length

* Fix validator tests

* fix more tests

* fix mock validator

* Fix typo

* bunch of typos

* Update bytes.go

* Update BUILD.bazel

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

validator/db/kv/kv_test.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"testing"
 
+	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/testing/require"
 	"github.com/sirupsen/logrus"
 )
@@ -17,7 +18,7 @@ func TestMain(m *testing.M) {
 }
 
 // setupDB instantiates and returns a DB instance for the validator client.
-func setupDB(t testing.TB, pubkeys [][48]byte) *Store {
+func setupDB(t testing.TB, pubkeys [][fieldparams.BLSPubkeyLength]byte) *Store {
 	db, err := NewKVStore(context.Background(), t.TempDir(), &Config{
 		PubKeys: pubkeys,
 	})