[ftr] geoip ingest processor not working in serverless FTR config

[weltenwort]

🐞 Description

When running serverless FTR tests locally or in CI, the GeoIP ingest pipeline processor in the Elasticsearch cluster is not functional. Instead, it adds a field tags: "_geoip_database_unavailable_GeoLite2-City.mmdb" to all documents ingested via an ingest pipeline that contains it.

• 🔗 causes: [FLAKY ON MKI] x-pack/test_serverless/functional/test_suites/observability/dataset_quality/degraded_field_flyout.ts #202641

🐾 Steps to reproduce

1. During any serverless functional test, ingest any document into a data stream matching logs-apm.apps.*.
2. Observe how each document gains the tags field.

🔍 Background

• In order to function correctly, the geoip ingest processor requires a geoip database to be available.
• Usually Elasticsearch downloads a geoip database automatically when any ingest pipeline using that processor exists.
• The test cluster's docker network as created by the FTR framework does not offer a route to the internet.
• Since that wouldn't be advisable in CI anyway, a locally hosted provider of the geoip database files would probably be preferable.

[elasticmachine]

Pinging @elastic/appex-qa (Team:QA)