ESQL: `OrdinalsGroupingOperator` not reporting `process_nanos`

[nik9000]

Description

OrdinalsGroupingOperator, like the other operators, should include stuff like:

            "process_nanos": nnnnnnnn,
            "pages_processed": nn,
            "rows_received": nnnn,
            "rows_emitted": nnnn

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[nik9000]

It should probably group its process time for it's stages of operations. There are a bunch of interesting things to track inside of it actually.

[ivancea]

Discarded, as the operator was removed in #131133