Add HTTP OTLPMetricExporter test coverage for `max_export_batch_size`

[tammy-baylis-swi]

Is your feature request related to a problem?

Requested in #5015 that I add HTTP OTLPMetricExporter test coverage for max_export_batch_size with non-mocked export. Related also to #4577 and #5014

Describe the solution you'd like

Add test coverage without mocking export.

Describe alternatives you've considered

No response

Additional Context

No response

Would you like to implement a fix?

None

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