Merge bitcoindevkit/bdk#1682: test(wallet): create tx locktime cltv for a specific...

Merge bitcoindevkit/bdk#1682: test(wallet): create tx locktime cltv for a specific time

2c11d46d5c26f21fe564297f8766b888e1da3662 test(wallet): add check for a tx locktime cltv with timestamp (f3r10)

Pull request description:

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  ### Description
  This PR adds a unit test that checks the satisfaction of timestamp-based timelocks. The goal is to test the absolute time therefore the variable passed to the miniscript fragment `after` has to be equal to or greater that 500_000_000 otherwise it would be checking the block height.

  ### Notes to the reviewers

  <!-- In this section you can include notes directed to the reviewers, like explaining why some parts
  of the PR were done in a specific way -->
  This unit test tries to check if #642 is still an issue.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  ValuedMammal:
    ACK 2c11d46d

Tree-SHA512: 081918b772b2a7e52b02bbf764e4204d9d5e18febded9e5600798c3f46d2e35a9a72ffeeca6c9bf708b71b8cf66d6e502771b2f8d15bfca2629a9dfbc67f6298