test: enable functional tests with large rpc args for cli

Also, the following tests (for which self.supports_cli = False was not
set) will now work with --usecli:

feature_fastprune.py
feature_fee_estimation.py
feature_reindex_readonly.py
feature_taproot.py
mempool_package_rbf.py
p2p_net_deadlock.py
p2p_tx_download.py
rpc_packages.py

test/functional/p2p_opportunistic_1p1c.py

@@ -61,7 +61,6 @@ class PackageRelayTest(BitcoinTestFramework):
         self.extra_args = [[
             "-maxmempool=5",
         ]]
-        self.supports_cli = False
 
     def create_tx_below_mempoolminfee(self, wallet):
         """Create a 1-input 1sat/vB transaction using a confirmed UTXO. Decrement and use