Skip metadata upload if no new segment files to upload during refresh for remote store clusters

Is your feature request related to a problem? Please describe

In the refresh flow of remote store indexes, we determine the files to be uploaded, upload them and then upload the associated metadata. This, however, uploads the metadata even when there is no new files to upload. This can be optimised and metadata upload can be skipped for such cases.

https://github.com/opensearch-project/OpenSearch/blob/3966ed93beb2ff13854d2a6e1ff51dfa32295830/server/src/main/java/org/opensearch/index/shard/RemoteStoreRefreshListener.java#L266C21-L292

Describe the solution you'd like

Optimise the segments upload flow to skip metadata upload when there are no newer segment files.

Related component

No response

Describe alternatives you've considered

No response

Additional context

No response