message: Remove overlooked use of caf::string_view
diff: #include "caf/telemetry/metric_type.hpp"
  using namespace caf;
  -using namespace caf::literals;
  using namespace caf::telemetry;
  using namespace std::literals;
  @@ -64,7 +63,7 @@ some_request_duration_seconds_bucket{x="get",le="4"} 2 42000
  some_request_duration_seconds_bucket{x="get",le="+Inf"} 3 42000
  some_request_duration_seconds_sum{x="get"} 14 42000
  some_request_duration_seconds_count{x="get"} 3 42000
  -)"_sv);
  +)"sv);
  MESSAGE("multiple runs with the same timestamp generate the same output");
  auto ts = make_timestamp();
  std::string res1;
  