Merge bitcoin/bitcoin#28204: qa: Close SQLite connection properly

703b758 qa: Close SQLite connection properly (Hennadii Stepanov)

Pull request description:

  This PR is a follow-up for bitcoin/bitcoin#26462 that introduced a bug on Windows:
  ```
  >test\functional\wallet_descriptor.py
  ...
  PermissionError: [WinError 32] The process cannot access the file because it is being used by another process:
  ...
  ```

  From `sqlite3` Python module [docs](https://docs.python.org/3/library/sqlite3.html#how-to-use-the-connection-context-manager):
  > `Connection` object used as context manager only commits or rollbacks transactions, so the connection object should be closed manually.

ACKs for top commit:
  MarcoFalke:
    lgtm ACK 703b758
  theStack:
    utACK 703b758

Tree-SHA512: 35b1403507be06d1fc04e7e07ff56af5bcfe5013024671f0c1d9f3c41aacc4c777bcc6376ce82d720394e27450415d50ff5d5834ed388ec3f21503f86f1a42a5

Author: fanquake

test/functional/wallet_descriptor.py

@@ -235,9 +235,11 @@ def run_test(self):
         self.nodes[0].createwallet(wallet_name="crashme", descriptors=True)
         self.nodes[0].unloadwallet("crashme")
         wallet_db = os.path.join(self.nodes[0].wallets_path, "crashme", self.wallet_data_filename)
-        with sqlite3.connect(wallet_db) as conn:
+        conn = sqlite3.connect(wallet_db)
+        with conn:
             # add "cscript" entry: key type is uint160 (20 bytes), value type is CScript (zero-length here)
             conn.execute('INSERT INTO main VALUES(?, ?)', (b'\x07cscript' + b'\x00'*20, b'\x00'))
+        conn.close()
         assert_raises_rpc_error(-4, "Unexpected legacy entry in descriptor wallet found.", self.nodes[0].loadwallet, "crashme")