test: Make leaf_script mandatory when scriptpath is set in TaprootSignatureMsg

This removes the default value, because there should not be a use-case
to fall back to a an empty leaf_script by default. (If there was, it
could trivially be added back)

test/functional/feature_taproot.py

@@ -231,7 +231,7 @@ def default_sigmsg(ctx):
             codeseppos = get(ctx, "codeseppos")
             leaf_ver = get(ctx, "leafversion")
             script = get(ctx, "script_taproot")
-            return TaprootSignatureMsg(tx, utxos, hashtype, idx, scriptpath=True, script=script, leaf_ver=leaf_ver, codeseparator_pos=codeseppos, annex=annex)
+            return TaprootSignatureMsg(tx, utxos, hashtype, idx, scriptpath=True, leaf_script=script, leaf_ver=leaf_ver, codeseparator_pos=codeseppos, annex=annex)
         else:
             return TaprootSignatureMsg(tx, utxos, hashtype, idx, scriptpath=False, annex=annex)
     elif mode == "witv0":