Merge bitcoindevkit/bdk#2411: test(chain): simplify `test_classify_locked_descriptor_...

8d847163b797d6428c52c3f405dab8ccb7736132 test(chain): simplify the locked descriptor timelocks test (Dmenec)

Pull request description:

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  ### Description

  Closes #2406. Thanks @evanlinjin.

  Replaces `test_classify_locked_script_timelocks` with the simplified version @evanlinjin proposed in #2406, and renames it to `test_classify_locked_descriptor_timelocks` since it no longer parses the script.

ACKs for top commit:
  evanlinjin:
    ACK 8d847163b797d6428c52c3f405dab8ccb7736132

Tree-SHA512: 685ae188aa9a637913580ca21f3b50a379fee1478ede013f1b892051b712aa73a2fc23568faf1b694a249ee8bb11c4028a32693692c59af93eac08604f903683