test: run bitcoin-cli -ipcconnect check under valgrind with -datadir

This case invoked bitcoin-cli via raw subprocess.run() without the
valgrind wrapper (bypassing valgrind) and without -datadir (so it read
the default datadir's bitcoin.conf, e.g. ~/.bitcoin, and failed whenever
that real config was unusable). Build the command like the rest of the
framework: prepend binaries.valgrind_cmd and pass the node's -datadir so
the check runs under valgrind and depends only on the build's IPC
support, not the host environment.

test/functional/interface_bitcoin_cli.py

@@ -458,7 +458,8 @@ class TestBitcoinCli(BitcoinTestFramework):
             # This tests behavior when ENABLE_IPC is off. When it is on,
             # behavior is checked by the interface_ipc_cli.py test.
             self.log.info("Test bitcoin-cli -ipcconnect triggers error if not built with IPC support")
-            args = [self.binary_paths.bitcoincli, "-ipcconnect=unix", "-getinfo"]
+            # node.cli.options includes -rpcconnect which can't be combined with -ipcconnect, so pass just -datadir directly to keep bitcoin-cli on the test's bitcoin.conf
+            args = self.nodes[0].binaries.valgrind_cmd + [self.nodes[0].binaries.paths.bitcoincli, f"-datadir={self.nodes[0].datadir_path}", "-ipcconnect=unix", "-getinfo"]
             result = subprocess.run(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
             assert_equal(result.stdout, "error: bitcoin-cli was not built with IPC support\n")
             assert_equal(result.stderr, None)