[exporter/otlphttp] output includes non-JSON log data, causing JSON parsing errors

[mmynk]

Describe the bug
I am using the otlphttpexporter to export JSON data and consume it in Logstash. However, each exported dataset includes an additional log entry outside the JSON structure, which causes JsonParse errors in Logstash.

Is there a way to exclude the following line from the export, or must it be handled explicitly?

Steps to reproduce

1. Use otlphttpexporter with encoding: json.
2. Observe the additional log line in the output, alongside the JSON data.

{"resourceMetrics": ... }
10.20.30.40 - - [06/Sep/2024 14:56:04] "POST / HTTP/1.1" 200 -

What did you expect to see?
The last line 10.20.30.40 - - [06/Sep/2024 14:56:04] "POST / HTTP/1.1" 200 - should not appear alongside the JSON data.

What did you see instead?
A malformed JSON containing an additional log line outside the valid JSON structure.

What version did you use?
v0.108.1

What config did you use?

exporters:
  otlphttp:
    encoding: json
    metrics_endpoint: http://40.30.20.10:12345
    compression: none

Environment
Ubuntu 20.04
OpenTelemetry Collector: v0.108.1

Additional context
The additional line appears to be a log entry from the HTTP server.