message: Validation admin returns true for addHandler and removeHandler.
  config validation: ValidationAdmin should pretend that addHandler and removeHandler complete successfully
  Risk Level: Low.
  Testing: Manual testing.
  Docs Changes: No.
  Release Notes: No.
  Fixes
diff: namespace Envoy {
  namespace Server {
  +// Pretend that handler was added successfully.
  bool ValidationAdmin::addHandler(const std::string&, const std::string&, HandlerCb, bool, bool) {
  - return false;
  + return true;
  }
  -bool ValidationAdmin::removeHandler(const std::string&) { return false; }
  +bool ValidationAdmin::removeHandler(const std::string&) { return true; }
  const Network::Socket& ValidationAdmin::socket() { NOT_IMPLEMENTED_GCOVR_EXCL_LINE; }
  