[beat] Update mappings for APM Server aggregation metrics

[miltonhultgren]

A recent PR changes the shape of the documents for some APM metrics, which caused a breakage since the mappings didn't work.
This PR expands the mappings to the new object shape.

[miltonhultgren]

@elastic/apm-server This is in response to the changes introduced by elastic/apm-server#10330

The monitoring setup is complicated to say the least :)

[elasticmachine]

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• Start Time: 2023-03-16T17:35:47.581+0000

• Duration: 18 min 30 sec

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[elasticmachine]

Package beat - 0.1.1 containing this change is available at https://epr.elastic.co/search?package=beat

[simitt]

Apologies for coming back to this late. @miltonhultgren are you backporting this to 8.7?

[miltonhultgren]

@simitt No problem, last week was special! I decided to just fix up the failure by mapping the new fields (mostly because the Integrations require all existing fields to be mapped) but I'm happy to make further changes if your team want things done differently!