Merge bitcoin/bitcoin#31768: test: check scanning field from getwalletinfo

bb0879d test: check `scanning` field from `getwalletinfo` (brunoerg)

Pull request description:

  During a rescan, check that `getwalletinfo` returns properly information (the scanning field) about it.

ACKs for top commit:
  maflcko:
    lgtm ACK bb0879d
  arejula27:
    ACK [`bb0879d`](bitcoin/bitcoin@bb0879d)
  achow101:
    ACK bb0879d
  BrandonOdiwuor:
    Code Review ACK bb0879d
  Prabhat1308:
    re-ACK [`bb0879d`](bitcoin/bitcoin@bb0879d)

Tree-SHA512: 9bca1c1e813bf4f61a5621bdc0a5f5c2bcfb388ffe9dfacb821bf6954f6e0880140d72258dc93ab6b84efb54f55c682a17aebd42f6559d6cfac9998e6bc4e5b9

Author: achow101

test/functional/wallet_importdescriptors.py

@@ -24,6 +24,7 @@
 from test_framework.descriptors import descsum_create
 from test_framework.util import (
     assert_equal,
+    assert_greater_than,
     assert_raises_rpc_error,
 )
 from test_framework.wallet_util import (
@@ -705,6 +706,13 @@ def run_test(self):
             except JSONRPCException as e:
                 assert e.error["code"] == -4 and "Error: the wallet is currently being used to rescan the blockchain for related transactions. Please call `abortrescan` before changing the passphrase." in e.error["message"]
 
+            wallet_info = self.nodes[0].cli("-rpcwallet=encrypted_wallet").getwalletinfo()
+            try:
+                duration = wallet_info["scanning"]["duration"]
+                assert_greater_than(duration, 0)
+            except Exception:
+                assert "scanning" not in wallet_info
+
             assert_equal(importing.result(), [{"success": True}])
 
         assert_equal(temp_wallet.getbalance(), encrypted_wallet.getbalance())