treat 400 error as recoverable

Author: eli-darkly

src/LaunchDarkly/Util.php

@@ -59,7 +59,7 @@ public static function newFeatureRequestEvent($key, $user, $variation, $value, $
  public static function isHttpErrorRecoverable($status)
  {
  if ($status >= 400 && $status < 500) {
- return ($status == 408) || ($status == 429);
+ return ($status == 400) || ($status == 408) || ($status == 429);
  }
  return true;
  }