Merge bitcoindevkit/bdk#1110: fix(esplora): use saturating_add in update_tx_graph()

bf9a4258496ef91bec4d15126d6e98a2450533ea ci: fix MSRV build by pinning tokio-util to 0.7.8 (Steve Myers)
d35668e76aa3ba429041305e54106c10429a8b1b ci(esplora): fix wasm cargo check by setting workspace resolver to version 2 (Steve Myers)
31d52e12c93469dc6af9a88eba42ad87315dd63b ci: fix msrv dependency versions for rustls-webpki and zip (Steve Myers)
6a5c9d7a00bfddbdf6bd279d003fefe3958dccc1 fix(esplora): use saturating_add in update_tx_graph() (Steve Myers)
4d1a9fd47ab61e1cba2d01fe1191df8c0064c767 test(esplora): add async_ext and blocking_ext integration tests (Steve Myers)

Pull request description:

  ### Description

  This fixes overflow error when calling update_tx_graph() from update_tx_graph_without_keychain().

  ### Notes to the reviewers

  You can reproduce the error by reverting 66a2bf5ef2a70f8de41941d2f07bec776d152b96.

  The tests could use some cleanup but get the job done for this PR.

  ### Changelog notice

  None

  ### 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

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [x] I've added tests to reproduce the issue which are now passing
  * [ ] I'm linking the issue being fixed by this PR

Top commit has no ACKs.

Tree-SHA512: eace00e0c289a7ac161985c4b8e46ad660ec0d6777cd74027ef1f0ab245daea87e34258233281796efb60473cf4f18d2647c090a14c0f05f3dc8a1950ebe9dab