Remove unnecessary error from retryOnTimeoutActivity

What changed?
Removed unnecessary error from retryOnTimeoutActivity from canary/retry.go workflow

Why?
The error was introduced because there was a bug in the service that would allow completion from a previous attempt. The bug has been corrected.

How did you test it?
Executed the workflow without the error and confirmed that it completed successfully.

Potential risks

Release notes

Documentation Changes

canary/retry.go

@@ -115,9 +115,6 @@ func retryOnTimeoutActivity(ctx context.Context, scheduledTimeNanos int64) (int,
 	if info.Attempt < 3 {
 		activity.RecordHeartbeat(ctx, info.Attempt*100)
 		time.Sleep(2 * info.HeartbeatTimeout)
-		// Currently we have a server bug which accepts completion from different attempt
-		// For now fail the activity
-		return 0, errRetryableActivityError
 	}
 
 	return progress, nil