Add more debug logs to understand if statement-distribution misbehaving (#3476)

cherry picked from master commit
b9c792a4



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Add more debug logs to understand if statement-distribution is in a bad
state, should be useful for debugging
https://github.com/paritytech/polkadot-sdk/issues/3314 on production
networks.

Additionally, increase the number of parallel requests should make,
since I notice that requests take around 100ms on kusama, and the 5
parallel request was picked mostly random, no reason why we can do more
than that.

Signed-off-by: Alexandru Gheorghe <[email protected]>
Co-authored-by: ordian <[email protected]>