Fix GeoIpDownloaderIT.testInvalidTimestamp

[nielsbauman]

The GeoIP expiration logic assumes that the md5 hashes of the databases change over time, as it deletes all database chunks from the .geoip_databases index. If the hashes do not change, no new database chunks are indexed and so the ingest nodes fail to download the databases as there are no chunks to download.
In this test suite, we don't have a way to change the database files served by the fixture, and thus change their md5 hashes.
Since we assume that in a real-world scenario the database files change over time, we are ok with skipping this part of the test.

See #128284 (comment) for a detailed investigation.

Closes #128284

[Copilot]

Pull Request Overview

Fixes a flaky test by removing the problematic assertion that assumed database files would be re-downloaded after resetting the validity setting. The test was failing because the GeoIP expiration logic deletes database chunks but doesn't re-download them when MD5 hashes remain unchanged, which is the case in the test fixture environment.

• Removed the second half of testInvalidTimestamp that attempted to verify database re-download after resetting validity
• Added a custom IndexSettingProvider to disable request cache for the .geoip_databases index, ensuring cache doesn't mask the deletion of database chunks
• Unmuted the test in muted-tests.yml

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
muted-tests.yml	Removed test mute entry for testInvalidTimestamp
GeoIpDownloaderIT.java	Modified test to skip re-download verification, added cache-disabling plugin, and added assertion to verify chunk deletion

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[elasticsearchmachine]

Pinging @elastic/es-data-management (Team:Data Management)

[szybia]

lgtm

my impression is that this doesn't seem too pressing to test, as a reviewer i'd be digging more into why we can't change the hashes, but 🤷