Enable https proxies in Telemetry SDK

[cayetanocobaleda]

As things stand today, the Telemetry SDK uses the OkHttpClient, which does not fully support HTTPS proxies:

square/okhttp#3787

This impacts products built on top of the Telemetry SDK. For example, our implementation of the Java Flight Recorder, which is currently bundled with the Java agent, uses the Telemetry SDK under the hood. The result of this is that if a customer is using an HTTPS proxy, most Java agent telemetry data is sent up without issue, but JFR data fails with the following exception:

2023-05-29T15:03:47,556+1000 [1 73] com.newrelic INFO: [MetricBatch] - Batch sending failed. Backing off 15000 MILLISECONDS
2023-05-29T15:03:47,866+1000 [1 74] com.newrelic WARN: IOException (message: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target, cause: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target) while trying to send data to New Relic. EventBatch retry recommended

Because the issue lies with the OkHttpClient, we cannot easily implement a fix unless one of two things happens:

OkHttpClient implements support for HTTPS proxies.
We refactor the Telemetry SDK to use a different HttpClient.

[workato-integration]

https://issues.newrelic.com/browse/NR-142830

[workato-integration]

The problem is a duplicate of an existing issue.