aggregator_example_test.go is out of date.

[MadVikingGod]

Problem Statement

aggregator_example_test.go is out of date and doesn't represent how aggregators are built and used anymore.

Proposed Solution

Update the example to show how these aggregations are currently built.

Alternatives

Remove this example.

Additional Context

I believe this file was made before the meter had a pipeline structure. This was an example of how the Meter/MeterProvider might use the Aggregations. Now that the pipeline exists, I question if this still provides us value, especially if we can fundamentally change the use of Aggregators and not have this break.

[MrAlias]

Remove this example.

+1