Support global labels for aggregated metrics for RUM
Global labels can have high cardinality when used for RUM. They are not currently part of aggregated metrics since https://github.com/elastic/apm-server/pull/10624, to avoid causes for overflow buckets. This currently impacts apm data collected by the "rum-js", "js-base", "android/java", "iOS/swift" agents.
We should find a way to also support global labels for RUM.
Update the docs once this is completed, to undo the change in https://github.com/elastic/observability-docs/pull/3877
In version 8.10, global metrics for aggregated indices have still not been introduced. #11768
@b2ronn due to an often expected high cardinality in RUM global labels, we would need to find a different solution than just adding global labels as an aggregation dimension. This can also be a challenge for non-RUM setups, and we are thinking about a more global solution to this. But the task is not currently scheduled for implementation and will likely not be part of the next minor versions.
As an alternative, it may be worth to consider adding the capability for the admin of the APM server to define the list of permitted global labels for "rum-js," "js-base," "android/java," "iOS/swift"?