Move autoconfigure otlp tests

[jack-berg]

Resolves #4949.

This is likely an unreviewable change. Here's a summary of it and why its hard to break up:

• Ultimate goal is to move OTLP tests out of :sdk-extensions:autoconfigure and into :exporter:otlp.
• Unfortunately the OTLP tests in :sdk-extensions:autoconfigure provide a decent amount of coverage for the OtlpHttp{Signal}Exporters that doesn't otherwise exist. The OtlpGrpc{Signal}Exporters don't have this same problem because they have an abstract test class with a bunch of implementations.
• I've made up for this coverage deficiency by adding AbstractHttpTelemetryExporterTest and corresponding implementations. Its largely a copy of AbstractGrpcTelemetryExporterTest with changes as needed to reflect differences in grpc and http/protobuf.
• This allows the the OTLP tests to be deleted in there current form, since coverage exists elsewhere.
• However, new tests were needed to check that the SPI implementations interpret ConfigProperties and configure the builders correctly. The new Otlp{Signal}ExporterProviderTests provide this coverage. I thought about abstracting the common parts away, but concluded it would make the test code too hard to comprehend.

This could be reasonably broken up into two PRs, but even those would be pretty large and hard to review carefully.

[codecov]

Codecov Report

Base: 91.19% // Head: 91.06% // Decreases project coverage by -0.13% ⚠️

Coverage data is based on head (51c5b2f) compared to base (9dfb002).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5060      +/-   ##
============================================
- Coverage     91.19%   91.06%   -0.14%     
- Complexity     4877     4887      +10     
============================================
  Files           553      553              
  Lines         14402    14460      +58     
  Branches       1375     1380       +5     
============================================
+ Hits          13134    13168      +34     
- Misses          879      898      +19     
- Partials        389      394       +5     

Impacted Files	Coverage Δ
...rter/otlp/internal/OtlpMetricExporterProvider.java	100.00% <100.00%> (ø)
...porter/otlp/internal/OtlpSpanExporterProvider.java	100.00% <100.00%> (ø)
...r/otlp/internal/OtlpLogRecordExporterProvider.java	100.00% <100.00%> (ø)
...etry/exporter/internal/okhttp/JsonRequestBody.java	0.00% <0.00%> (-100.00%)	⬇️
...emetry/exporter/internal/grpc/GrpcRequestBody.java	56.52% <0.00%> (-43.48%)	⬇️
...rter/otlp/http/metrics/OtlpHttpMetricExporter.java	84.61% <0.00%> (-7.70%)	⬇️
...metry/exporter/internal/okhttp/OkHttpExporter.java	89.39% <0.00%> (-6.07%)	⬇️
...lp/http/metrics/OtlpHttpMetricExporterBuilder.java	95.00% <0.00%> (-5.00%)	⬇️
...lemetry/exporter/internal/otlp/OtlpConfigUtil.java	89.68% <0.00%> (-2.39%)	⬇️
...etry/exporter/internal/otlp/logs/LogMarshaler.java	67.10% <0.00%> (-1.32%)	⬇️
... and 5 more

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[jkwatson]

hmm. This all looks good, but it looks like it reduced coverage a bit. Any idea how difficult it would be to backfill those gaps?

[jkwatson]

Not happy with the slightly reduced coverage numbers, but otherwise looks fine to me.

[jack-berg]

I've added some tests to increase the coverage. The coverage should be equivalent now. I think any remaining diff is just one of those quirks with the codecov tool.