move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/telegram/internal/e2etest/auth.go

@@ -0,0 +1,58 @@
+package e2etest
+
+import (
+	"context"
+
+	"github.com/cenkalti/backoff/v4"
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/auth"
+)
+
+func (s *Suite) createFlow(ctx context.Context) (auth.Flow, error) {
+	var ua auth.UserAuthenticator
+	for {
+		ua = auth.Test(s.rand, s.dc)
+		phone, err := ua.Phone(ctx)
+		if err != nil {
+			return auth.Flow{}, err
+		}
+
+		s.usedMux.Lock()
+		if _, ok := s.used[phone]; !ok {
+			s.used[phone] = struct{}{}
+			s.usedMux.Unlock()
+			break
+		}
+		s.usedMux.Unlock()
+	}
+
+	return auth.NewFlow(ua, auth.SendCodeOptions{}), nil
+}
+
+// Authenticate authenticates client on test server.
+func (s *Suite) Authenticate(ctx context.Context, client auth.FlowClient) error {
+	for {
+		flow, err := s.createFlow(ctx)
+		if err != nil {
+			return errors.Wrap(err, "create flow")
+		}
+
+		if err := flow.Run(ctx, client); err != nil {
+			if errors.Is(err, auth.ErrPasswordNotProvided) {
+				continue
+			}
+
+			return errors.Wrap(err, "run flow")
+		}
+		return nil
+	}
+}
+
+// RetryAuthenticate authenticates client on test server.
+func (s *Suite) RetryAuthenticate(ctx context.Context, client auth.FlowClient) error {
+	bck := backoff.WithContext(backoff.NewExponentialBackOff(), ctx)
+	return backoff.Retry(func() error {
+		return s.Authenticate(ctx, client)
+	}, bck)
+}