fix jaegerremote parser to use jsonpb unmarshaler

[tonybase]

Failed to parse sampling strategy response: json: cannot unmarshal string into Go struct field SamplingStrategyResponse.strategyType of type api_v2.SamplingStrategyType:

{"strategyType":"PROBABILISTIC","probabilisticSampling":{"samplingRate":1},"operationSampling":{"defaultSamplingProbability":1,"defaultLowerBoundTracesPerSecond":0,"perOperationStrategies":[{"operation":"/health","probabilisticSampling":{"samplingRate":0}},{"operation":"/metrics","probabilisticSampling":{"samplingRate":0}}}],"defaultUpperBoundTracesPerSecond":0}}

[linux-foundation-easycla[bot]]

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• :white_check_mark: login: tonybase / name: Tony Chen (d02758470adf5cd1750d3fc1f61f8cd679fd9441)

[codecov[bot]]

Codecov Report

Merging #2623 (944e1b4) into main (3091f5e) will increase coverage by 5.0%. The diff coverage is 0.0%.

:exclamation: Current head 944e1b4 differs from pull request most recent head 9b204a7. Consider uploading reports for the commit 9b204a7 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2623     +/-   ##
=======================================
+ Coverage   69.4%   74.4%   +5.0%     
=======================================
  Files        145     145             
  Lines       6707    6708      +1     
=======================================
+ Hits        4655    4993    +338     
+ Misses      1938    1567    -371     
- Partials     114     148     +34     

Impacted Files	Coverage Δ
samplers/jaegerremote/sampler_remote.go	86.8% <0.0%> (-0.6%)	:arrow_down:
instrumentation/net/http/otelhttp/config.go	87.8% <0.0%> (+7.5%)	:arrow_up:
instrumentation/runtime/runtime.go	74.0% <0.0%> (+74.0%)	:arrow_up:
instrumentation/host/host.go	74.4% <0.0%> (+74.4%)	:arrow_up:
instrumentation/host/version.go	100.0% <0.0%> (+100.0%)	:arrow_up:
instrumentation/runtime/version.go	100.0% <0.0%> (+100.0%)	:arrow_up:

[hanyuancheung]

This PR should implement in your local-copy version, instead of being implemented in contrib. If you use jsonpb to Marshal, you should also copy and reimplement the jsonpb Unmarshal. But I don't think this is the standard way according to the otel specification. PTAL.

[dmathieu]

This should include an automated test