Order `Sync*` Requests fields

[SantiagoPittella]

I think we should adapt a convention where all "sync" requests specify block from/to as the first two fields. For this message this would look something like:

message CheckNullifiersByPrefixRequest {
    fixed32 block_from = 1;
    optional fixed32 block_to = 2;
    uint32 prefix_len = 3;
    repeated uint32 nullifiers = 3;
}

This is already the case for SyncStorageMapsRequest and SyncAccountVaultRequest, and we should make it the same for SyncNotesRequest (in a different PR - let's make an issue for this).

Originally posted by @bobbinth in #1191 (comment)

[bobbinth]

Ah - just saw this. I think it is fine to merge #1191 and then address this separately, but I'd do one right after the other.

[SantiagoPittella]

The reorder of the fields in the now called SyncNullifiers method was finally implemented in the merged PR. The other Sync* methods already have this ordering, using block_from and block_to for the ones that have pagination, and just block_num for the ones that doesn't implement pagination. Can we consider this issue as completed? @bobbinth

[bobbinth]

Yes, closed by #1191.