ci: remove duplicated cache-key-suffix keys from check-ubuntu.yml

.github/workflows/check-ubuntu.yml

@@ -47,7 +47,9 @@ jobs:
           # Own build-cache store (setup-soldr#237): with no suffix this job
           # shared one Cargo.lock-keyed entry with ~10 other workflows, and
           # the first small job to save it (165 MB) froze it -- an exact hit
-          # never re-saves -- so every run recompiled ~240 crates.
+          # never re-saves -- so every run recompiled ~240 crates. Distinct
+          # from python-facade-tests below, whose 166MB cache otherwise won
+          # the shared entry over this job's 479MB save.
           cache-key-suffix: check-ubuntu
           cache: true
           build-cache: true
@@ -63,11 +65,6 @@ jobs:
           # the steady-state size so the action only flags genuinely
           # runaway caches. Hard cap stays at the action default (6 GiB).
           cache-payload-warn-bytes: 2GiB
-          # Distinct from python-facade-tests below. With one shared key the
-          # job that finishes first owns the immutable entry: the facade job's
-          # 166MB fbuild-python-only cache won over this job's 479MB save, and
-          # PRs restored it at a 28-32% hit rate.
-          cache-key-suffix: check-ubuntu
 
       # No separate `cargo check`: clippy type-checks the same
       # `--workspace --all-targets` set, so a prior check only re-did that work.
@@ -119,7 +116,6 @@ jobs:
           target-cache: true
           prebuild-deps: none
           linker: platform-default
-          cache-key-suffix: python-facades
       - name: Run embedded-CPython facade tests
         run: |
           uv python install 3.10