Fix 0007-dispute-freshly-finalized.zndsl failing (#3893)

Test started failing after
66051ad
which enabled approval coalescing, that was expected to happen because
the test required an polkadot_parachain_approval_checking_finality_lag
of 0, which can't happen with max_approval_coalesce_count greater than 1
because we always delay the approval for no_show_duration_ticks/2 in
case we can coalesce it with other approvals.


So relax a bit the restrictions, since we don't actually care that the
lags are 0, but the fact the finalities are progressing and are not
stuck.

Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>

polkadot/zombienet_tests/functional/0007-dispute-freshly-finalized.zndsl

@@ -21,9 +21,9 @@ honest: reports polkadot_parachain_candidate_dispute_concluded{validity="valid"}
 honest: reports polkadot_parachain_candidate_dispute_concluded{validity="invalid"} is 0 within 100 seconds
 
 # Check lag - approval
-honest: reports polkadot_parachain_approval_checking_finality_lag is 0
+honest: reports polkadot_parachain_approval_checking_finality_lag is lower than 2
 
 # Check lag - dispute conclusion
-honest: reports polkadot_parachain_disputes_finality_lag is 0
+honest: reports polkadot_parachain_disputes_finality_lag is lower than 2