script: add SCRIPT_ERR_TAPSCRIPT_EMPTY_PUBKEY

Empty public keys in tapscript are rejected by consensus rules, independent of SCRIPT_VERIFY_STRICTENC. Add SCRIPT_ERR_TAPSCRIPT_EMPTY_PUBKEY to distinguish this from STRICTENC policy failures currently reported as SCRIPT_ERR_PUBKEYTYPE.

src/test/script_tests.cpp

@@ -92,6 +92,7 @@ static ScriptErrorDesc script_errors[]={
     {SCRIPT_ERR_WITNESS_MALLEATED_P2SH, "WITNESS_MALLEATED_P2SH"},
     {SCRIPT_ERR_WITNESS_UNEXPECTED, "WITNESS_UNEXPECTED"},
     {SCRIPT_ERR_WITNESS_PUBKEYTYPE, "WITNESS_PUBKEYTYPE"},
+    {SCRIPT_ERR_TAPSCRIPT_EMPTY_PUBKEY, "TAPSCRIPT_EMPTY_PUBKEY"},
     {SCRIPT_ERR_OP_CODESEPARATOR, "OP_CODESEPARATOR"},
     {SCRIPT_ERR_SIG_FINDANDDELETE, "SIG_FINDANDDELETE"},
 };