[BUG] DistributionDownloader does not support ARM64 bundles.

[mch2]

Describe the bug
Currently DistributionDownloader is only fetching -x64 bundles published by CI.

DistributionDownloader needs to be updated to fetch -arm64 bundles if the host architecture is ARM64.

Link

To Reproduce
Steps to reproduce the behavior:

1. From an ARM64 machine, clone OpenSearch 1.0 and Update DistributionDownload plugin to intentionally point to an incorrect path here . This is so that we can fail and check the bundle classifier requested by default.
2. run ./gradlew publishToMavenLocal -Dbuild.snapshot=false
3. Clone any plugin, ex anomaly-detection and run ./gradlew integTest
4. See that tests fails (because of the wrong path) but that we are fetching the wrong bundle -
5. ‘https://artifacts.opensearch.org/release-candidates/NOTAREALPATH/opensearch/1.0.0/opensearch-min-1.0.0-linux-x64.tar.gz’

Expected behavior
The plugin should attempt to fetch ‘https://artifacts.opensearch.org/release-candidates/NOTAREALPATH/opensearch/1.0.0/opensearch-min-1.0.0-linux-arm64.tar.gz’