Increase non-signer threshold to 4k

This limit is here to keep the transaction from being able to go over
the max transaction size, but investigation and calculation revealed
that we can push it much higher than 300.

Author: jagerman

contracts/ServiceNodeRewards.sol

@@ -74,7 +74,7 @@ contract ServiceNodeRewards is Initializable, Ownable2StepUpgradeable, PausableU
         isStarted                   = false;
         totalNodes                  = 0;
         blsNonSignerThreshold       = 0;
-        blsNonSignerThresholdMax    = 300;
+        blsNonSignerThresholdMax    = 4000;
         proofOfPossessionTag        = buildTag("BLS_SIG_TRYANDINCREMENT_POP");
         rewardTag                   = buildTag("BLS_SIG_TRYANDINCREMENT_REWARD");
         exitTag                     = buildTag("BLS_SIG_TRYANDINCREMENT_EXIT");