A field_caps request on on 1000 indexes takes a huge amount of memory

[fmassot]

The searcher gets OOMKilled each time I send a field_caps request. I'm not sure why we take a lot of memory. Each split has around 10 fields.

[PSeitz]

Should be fixed with: https://github.com/quickwit-oss/quickwit/pull/4922

[PSeitz]

Another improvement would be to store aggregations of field caps in the cache instead per split one entry