new dictionary limit flag, decouple with batchSize

[ianhe8x]

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Description

When we construct dictionary query, we set first: batchSize.toString(), which may leads to more query requests if batchSize is small. The thing is we change batchSize mostly considering memory usage and rpc ratelimits, not dictionary queries.

Details

We should use a separated flag for dictionary limit, and default it to a larger value like 100