Add metrics for PeriodicMetricReader

[anuraaga]

This adds the last SDK metric, for the metric reader. Been a while since previous PR since I forgot about it 😅

https://opentelemetry.io/docs/specs/semconv/otel/sdk-metrics/#metric-otelsdkmetric_readercollectionduration

[anuraaga]

Couldn't think of a reason to not do this

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.24%. Comparing base (b56bc54) to head (bcf2b2b).
⚠️ Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
...io/opentelemetry/sdk/metrics/SdkMeterProvider.java	83.33%	2 Missing ⚠️
...dk/metrics/export/MetricReaderInstrumentation.java	88.88%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8038      +/-   ##
============================================
+ Coverage     90.16%   90.24%   +0.07%     
- Complexity     7478     7608     +130     
============================================
  Files           834      839       +5     
  Lines         22559    22846     +287     
  Branches       2239     2276      +37     
============================================
+ Hits          20341    20618     +277     
- Misses         1515     1519       +4     
- Partials        703      709       +6     

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[jack-berg]

Suggested change

	void setMeterProvider(MeterProvider meterProvider) {
	private void setMeterProvider(MeterProvider meterProvider) {

[jack-berg]

Makes me think that SdkTracerProvider, SdkLoggerProvider should cascade set meter provider on all child components (i.e. BatchSpanProcessor, exporters, etc). Problem is, the setMeterProvider methods on child components are on the builders... Probably could have had something more elegant with some foresight. Too bad.

[otelbot]

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