[Logs SDK] Print InstrumentationScope as part of Logs ostream exporter.

[lalitb]

Describe your environment N/A

Steps to reproduce
Run ostream exporter for logs.

What is the expected behavior?
It should dump instrumentation scope fields along with others.

What is the actual behavior?
Instrumentation scope fields are not dumped as seen from the unit-test - https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/ostream/test/ostream_log_test.cc

  std::vector<std::string> expected_output{
      "{\n"
      "  timestamp          : " +
          std::to_string(now.time_since_epoch().count()) +
          "\n"
          "  observed_timestamp : " +
          std::to_string(now.time_since_epoch().count()) +
          "\n"
          "  severity_num       : 1\n"
          "  severity_text      : TRACE\n"
          "  body               : Message\n",
      "  resource           : \n",
      "telemetry.sdk.version: " OPENTELEMETRY_VERSION "\n",
      "telemetry.sdk.name: opentelemetry\n",
      "telemetry.sdk.language: cpp\n",
      "  attributes         : \n"
      "  trace_id           : 00000000000000000000000000000000\n"
      "  span_id            : 0000000000000000\n"
      "  trace_flags        : 00\n"
      "}\n"};

Additional context
N/A

[github-actions]

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