C++17 compatibility: add a non-const char* overload.

C++17 adds a non-const std::basic_string::data, so non-const std::strings in the
test are `char*` and the const std::strings are `const char*`. See
https://en.cppreference.com/w/cpp/string/basic_string/data for details.

Without adding the non-const overload, the varargs overload is preferred, leading
to static_assert failures:

  In file included from hardware/interfaces/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp:33:
  In file included from hardware/interfaces/keymaster/3.0/vts/functional/authorization_set.h:20:
  hardware/interfaces/keymaster/3.0/vts/functional/keymaster_tags.h:257:5: error: static_assert failed "Authorization other then TagType::BOOL take exactly one parameter."
  static_assert(tag_type == TagType::BOOL || (sizeof...(args) == 1),
  ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  hardware/interfaces/keymaster/3.0/vts/functional/authorization_set.h:213:19: note: in instantiation of function template specialization 'android::hardware::keymaster::V3_0::Authorization<android::hardware::keymaster::V3_0::TagType::BYTES, android::hardware::keymaster::V3_0::Tag::ASSOCIATED_DATA, char *, unsigned long>' requested here
  push_back(Authorization(tag, std::forward<Value>(val)...));
  ^
  hardware/interfaces/keymaster/3.0/vts/functional/authorization_set.h:245:9: note: in instantiation of function template specialization 'android::hardware::keymaster::V3_0::AuthorizationSet::push_back<android::hardware::keymaster::V3_0::TypedTag<android::hardware::keymaster::V3_0::TagType::BYTES, android::hardware::keymaster::V3_0::Tag::ASSOCIATED_DATA>, char *, unsigned long>' requested here
  push_back(ttag, std::forward<ValueType>(value)...);
  ^
  hardware/interfaces/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp:3426:35: note: in instantiation of function template specialization 'android::hardware::keymaster::V3_0::AuthorizationSetBuilder::Authorization<android::hardware::keymaster::V3_0::TypedTag<android::hardware::keymaster::V3_0::TagType::BYTES, android::hardware::keymaster::V3_0::Tag::ASSOCIATED_DATA>, char *, unsigned long>' requested here
  AuthorizationSetBuilder().Authorization(TAG_ASSOCIATED_DATA, aad.data(), aad.size());
  ^

Bug: http://b/111067277
Test: builds
Change-Id: I3d70fb5a41db16cc9dff50364cd793e0c3510ed0