test: add functional test for multisig flow with descriptor wallets and PSBTs

test/functional/test_runner.py

@@ -204,6 +204,7 @@ BASE_SCRIPTS = [
     'feature_assumevalid.py',
     'example_test.py',
     'wallet_txn_doublespend.py --legacy-wallet',
+    'wallet_multisig_descriptor_psbt.py',
     'wallet_txn_doublespend.py --descriptors',
     'feature_backwards_compatibility.py --legacy-wallet',
     'feature_backwards_compatibility.py --descriptors',