Delay circuit breaker release until fetch response is sent

[drempapis]

Circuit breaker bytes were being released too early in the fetch phase. The bytes were released immediately after building SearchHits in FetchPhase.buildSearchHits(), but before the response was serialized and sent to the coordinator node. This created a timing window where:

1. `SearchHits are still in memory, consuming resources
2. Circuit breaker has already released the bytes, believing the memory is freed
3. This leads to circuit breaker undercounting, potentially allowing OOM conditions, especially for small setups with low heap resources.

This PR fixes the timing issue by delaying circuit breaker release until after the response has been successfully sent to the coordinator. We achieve this by:

1. Storing circuit breaker bytes in FetchSearchResult when hits are built
2. Releasing after transmission via listener wrappers that free bytes after listener.onResponse() completes
3. Handling exceptions safely by releasing immediately if an error occurs before the result is created

[elasticsearchmachine]

Pinging @elastic/es-search-foundations (Team:Search Foundations)

[drempapis]

@elasticmachine run elasticsearch-ci/part-1