Merge bitcoindevkit#2120: fix(chain): forward confirmation_height_upper_bound in Anchor implementation for &A

5d97e13 fix(chain): forward `confirmation_height_upper_bound` in `Anchor` impl for `&A` (志宇)

Pull request description:

  ### Description

  The blanket `Anchor` impl for `&A` was missing the `confirmation_height_upper_bound` method, causing it to fall back to the default implementation instead of delegating to the inner type.

  ### Changelog notice

  ```md
  Fixed:

  - The `Anchor::confirmation_height_upper_bound` impl was missing for `&A`, causing it to fallback to the default impl.
  ```

  ### 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~~
  ~~* [ ] I've added tests to reproduce the issue which are now passing~~
  ~~* [ ] I'm linking the issue being fixed by this PR~~

ACKs for top commit:
  ValuedMammal:
    ACK 5d97e13
  Dmenec:
    tACK 5d97e13

Tree-SHA512: baea97e5adb6fb1953e570339ec6826aa1ed84ff7914c56a4b1480c7df9218c782d7343a458e4f0e2427c12487dddd89cf067f722f868ca0c6584b44d731e56b

Author: ValuedMammal

crates/chain/src/tx_data_traits.rs

@@ -81,6 +81,10 @@ impl<A: Anchor> Anchor for &A {
     fn anchor_block(&self) -> BlockId {
         <A as Anchor>::anchor_block(self)
     }
+
+    fn confirmation_height_upper_bound(&self) -> u32 {
+        <A as Anchor>::confirmation_height_upper_bound(self)
+    }
 }
 
 impl Anchor for BlockId {