feat(sdk-metrics)!: extract IMetricReader interface and use it over abstract class

[pichlermarc]

Which problem is this PR solving?

We periodically run into problems since private properties in classes cause the type to be incompatible between versions. This PR fixes that for MetricReader by extracting an interface which we then use instead of the abstract class type in our public interface.

In this PR MetricReader type stays as-is, but this is marked as a breaking change since we technically narrow down what's being provided by MeterProviderOptions.

Part of #5283

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.63%. Comparing base (c408d21) to head (d88e876).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5311      +/-   ##
==========================================
+ Coverage   94.62%   94.63%   +0.01%     
==========================================
  Files         323      323              
  Lines        8071     8071              
  Branches     1640     1640              
==========================================
+ Hits         7637     7638       +1     
+ Misses        434      433       -1     

Files with missing lines	Coverage Δ
...imental/packages/opentelemetry-sdk-node/src/sdk.ts	96.93% <100.00%> (ø)
packages/sdk-metrics/src/MeterProvider.ts	100.00% <ø> (ø)
packages/sdk-metrics/src/export/MetricReader.ts	100.00% <100.00%> (ø)
packages/sdk-metrics/src/state/MetricCollector.ts	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes