Similar to Kusama, our approach on Polkadot involves adjusting the `setOnDemandMaxQueueSize` to 500. This change stems from an observation on Rococo, where a parachain's batch call for about 5,000 orders in a block, combined with a surplus of on-demand cores, resulted in notably slow block import times, as detailed in [the reported issue](https://github.com/paritytech/polkadot-sdk/issues/3051). As a temporary fix, we're limiting the total number of orders by modifying the configuration via `setOnDemandMaxQueueSize` to a smaller value, and for the initial launch, 500 is deemed a secure limit. Once a more permanent solution is implemented, the maximum number of orders can be reconsidered.


See [`Pallet::dispatch_whitelisted_call_with_preimage`].

Problem Statement:
- The current configuration of `setOnDemandMaxQueueSize` on Polkadot is causing slow block import times due to a surplus of on-demand cores.

Significance:
- This issue was observed on Rococo and is impacting the efficiency of block processing.

Proposed Solution:
- Adjust the `setOnDemandMaxQueueSize` to a value of 500 as a temporary fix to limit the total number of orders.

Expected Outcomes:
- Improved block import times and increased efficiency in block processing.

#489 Setting setOnDemandQueueMaxSize to 500