Merge #20322: test: Fix intermittent issue in wallet_listsinceblock

444412821e test: Fix intermittent issue in wallet_listsinceblock (MarcoFalke)

Pull request description:

ACKs for top commit:
  Empact:
    Code Review ACK https://github.com/bitcoin/bitcoin/pull/20322/commits/444412821e5349ce0e0b039d884583edb70c4399

Tree-SHA512: 86d47b1e3c8681dd479654589c894016ac81a3c96a34c3b4a75278b2af85054ea8c6f768e518a5322a4928d82d5e99105bbce0f4fa6a7a18c40e3e0799f9ab54

test/functional/wallet_listsinceblock.py

@@ -191,6 +191,7 @@ class ListSinceBlockTest(BitcoinTestFramework):
         address = key_to_p2wpkh(eckey.get_pubkey().get_bytes())
         self.nodes[2].sendtoaddress(address, 10)
         self.nodes[2].generate(6)
+        self.sync_all()
         self.nodes[2].importprivkey(privkey)
         utxos = self.nodes[2].listunspent()
         utxo = [u for u in utxos if u["address"] == address][0]