Merge bitcoindevkit/bdk#2325: fix(electrum): propagate transport errors when syncing...

edbf4a38847f0fc96f7aad72fbda0221d9c7e063 test(electrum): cover transport errors when syncing outpoints (chaitika)
84b0acf323e2f95919f39a3c3102925ce64174dd fix(electrum): propagate transport errors when syncing outpoints (chaitika)

Pull request description:

  ### Description

  Fixes #2293

  `populate_with_outpoints` discarded every `fetch_tx` error, so a connection/TLS/timeout failure made `sync` return `Ok` without data for the outpoint.

  It now skips only on `Error::Protocol` and propagates other errors, matching `populate_with_txids`.

  ### Changelog notice

   - `bdk_electrum`: `sync` now returns an error instead of silently skipping an outpoint when fetching its transaction fails for a non-protocol reason

  ### Checklists
  #### All Submissions:
  * [X] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  #### Bugfixes:
  * [ ] This pull request breaks the existing API
  * [X] I've added tests to reproduce the issue which are now passing
  * [X] I'm linking the issue being fixed by this PR

ACKs for top commit:
  evanlinjin:
    ACK edbf4a38847f0fc96f7aad72fbda0221d9c7e063

Tree-SHA512: 182464b58b9ea3a1637f4b9fb9a1b0aff878b48aea806691c7938ca14459711043a4695402b739a000c5744cc6541f17cdaa68964a38536524213ded7db83a09

diff --cc crates/electrum/src/bdk_electrum_client.rs
Simple merge

diff --cc crates/electrum/tests/test_electrum.rs
Simple merge