Skip privacy-pools in soroban-examples CI (#1811)

### What
Exclude the `privacy-pools` example from the soroban-examples CI matrix.

### Why
It depends on `soroban-poseidon`, which transitively depends on
`soroban-sdk` from crates.io. Cargo cannot override a transitive
dependency when the version does not match the semver compatibility
range defined by the importer, resulting in two copies of `soroban-sdk`
and duplicate `panic_impl` lang item errors.

Close #1723

---------

Co-authored-by: mootz12 <38118608+mootz12@users.noreply.github.com>

Author: leighmcculloch

.github/workflows/test-with-soroban-examples.yml

@@ -42,6 +42,16 @@ jobs:
       matrix:
         working-directory: ${{ fromJSON(needs.collect-examples.outputs.dirs) }}
         experimental_spec_shaking_v2: [true, false]
+        # Exclude examples that depend on crates.io packages that transitively
+        # depend on soroban-sdk (e.g. soroban-poseidon). Cargo does not provide
+        # a way to override the version of soroban-sdk required as a transitive
+        # dependency of another dependency where the version to override is a
+        # different major version or does not match the semver compatibility
+        # defined by the importer, causing two copies of soroban-sdk to be
+        # compiled and duplicate lang item (panic_impl) errors.
+        # https://github.com/stellar/rs-soroban-sdk/issues/1723
+        exclude:
+        - working-directory: privacy-pools
     defaults:
       run:
         working-directory: soroban-examples/${{ matrix.working-directory }}