Merge bitcoin/bitcoin#21359: rpc: include_unsafe option for fundrawtransaction

11d6459b6e rpc: include_unsafe option for fundrawtransaction (t-bast)

Pull request description:

  Allow RPC users to opt-in to unsafe inputs when funding a raw transaction.

  Applications that need to manage a complex RBF flow (such as lightning nodes using anchor outputs) are very limited if they can only use safe inputs.

  I also added this option to `send` and `walletcreatefundedpsbt` who internally delegate to `fundrawtransaction`.

  Fixes #21299

ACKs for top commit:
  laanwj:
    Code review ACK 11d6459b6e

Tree-SHA512: 5e542a4febcfd6f41cf784678ff02ec9282eae2082c274983f72c5ea87b7ebbe1bd5fdc6a020d7a9d5996157754eb4966b8aeb6c1ceebf0b1519f735579b8bac

test/functional/rpc_psbt.py

@@ -402,6 +402,14 @@ class PSBTTest(BitcoinTestFramework):
         # We don't care about the decode result, but decoding must succeed.
         self.nodes[0].decodepsbt(double_processed_psbt["psbt"])
 
+        # Make sure unsafe inputs are included if specified
+        self.nodes[2].createwallet(wallet_name="unsafe")
+        wunsafe = self.nodes[2].get_wallet_rpc("unsafe")
+        self.nodes[0].sendtoaddress(wunsafe.getnewaddress(), 2)
+        self.sync_mempools()
+        assert_raises_rpc_error(-4, "Insufficient funds", wunsafe.walletcreatefundedpsbt, [], [{self.nodes[0].getnewaddress(): 1}])
+        wunsafe.walletcreatefundedpsbt([], [{self.nodes[0].getnewaddress(): 1}], 0, {"include_unsafe": True})
+
         # BIP 174 Test Vectors
 
         # Check that unknown values are just passed through