[system tests] [transforms] Support commas in the source indices definition

[mrodm]

Relates #2341

Support to check transforms which source indices definition contains a list of comma-separated strings.

For instance (link)

source:
  index: "metrics-elasticsearch.stack_monitoring.index*,.monitoring-es-8*,metricbeat-*"

elastic-package needs to check each source index defined in the transform independently to validate whether or not it matches with the data stream tested.

Notes:

• Discovered that Fleet creates the transforms with logs- prefix
• Added a configuration to skip the validation of transforms (required for elasticsearch package).
  • In 8.10.1, the destination index is not created:
    • Even, if the destination index is created beforehand, it fails with the same error.
    • Probably related to the aggregations ? link
    • Error: "Source indices have been deleted or closed."
  • It looks like that the filters are too restrictive for the documents ingested in system test.
    Error: "must specify at least one document in [docs]"

[mrodm]

test integrations

[elastic-vault-github-plugin-prod]

Created or updated PR in integrations repository to test this version. Check elastic/integrations#12604

[elasticmachine]

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cc @mrodm

[mrodm]

Due to the errors found in the elasticsearch package from integrations (see PR description) when testing to check each index independently, it looks like it would be needed to add this kind of setting in the system tests.