[Failure store] Add selector support in the rollover API

[gmarouli]

In the #114992, we introduced the selector API in the multi-target syntax. We would like to replace the target_failure_store query param with the :: syntax in the rollover API. For example:

# Rollover data stream backing indices
POST my-data-stream/_rollover

# equivalent
POST my-data-stream::data/_rollover

# Rollover data stream failure store
POST my-data-stream::failures/_rollover

# Throws an error since the rollover is an API that requires one write index to rollover.
POST my-data-stream::*/_rollover

[elasticsearchmachine]

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