Remove parallelization of get hybridscores

[VijayanB]

Description

This parallelization is not adding any value after comparing the benchmarks with and without this optimization. Hence removing it.

Issues Resolved

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed as per the DCO using --signoff

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[martin-gaievski]

Can you share rough results of benchmarks, is it the same latency or worse with and without parallel get scores?

[VijayanB]

Can you share rough results of benchmarks, is it the same latency or worse with and without parallel get scores?

Query Count	Vector Count	No of Vector Search Query	No of Term Query	No of Sub-queries	is parallel enabled	K	size	P50 ( client time in ms )	P90 ( client time in ms )	P99 ( client time in ms )
1000	50000	1	1	2	no	100	100	101	106	121
1000	50000	1	1	2	yes	100	100	101	107	122
1000	50000	2	1	3	no	100	100	100	108	149
1000	50000	2	1	3	yes	100	100	100	108	152
1000	50000	1	2	3	no	100	100	106	120	200
1000	50000	1	2	3	yes	100	100	106	122	205

[VijayanB]

Can you share rough results of benchmarks, is it the same latency or worse with and without parallel get scores?

Ran 10 experiments with and without this change, P50 looks same, whereas i see few degradation with P90 and P99 ( in few milliseconds) in 8 out of 10 experiments. This is also consistent with took time. However, i can take a follow up task on how to tune this to improve further .

[VijayanB]

I added skip change-log, while merging to main, will group it into 1.