Interval and Timeout properties of PeriodicExportingMetricReader always converted to seconds

[duncanpo]

`

r = opentelemetry.sdk.metrics.PeriodicExportingMetricReader(exp, "Interval", minutes(10))

r =

PeriodicExportingMetricReader with properties:

MetricExporter: [1×1 opentelemetry.exporters.otlp.OtlpHttpMetricExporter]
      Interval: 600 sec
       Timeout: 30 sec

`
The conversion is unnecessary, and makes the value harder to read and understand

[duncanpo]

Fix is in metrics branch