[BUG][Remote Store] Repository base_path is ignored while uploading segments to remote segment store

[sachinpkale]

Describe the bug
Once we create repository:

curl -X PUT "localhost:9200/_snapshot/cluster_uuid" -H 'Content-Type: application/json' -d'{"type": "s3","settings": {"bucket": "my-repo","base_path": "test-upload"}}'

And the index is created with remote_store.enabled = true, the segments are uploaded to my-repo/my-index-1/0/segments/data path.

The path should be test-upload/my-repo/my-index-1/0/segments/data path