ci: fail fast on integration test binary cache miss (#447)

In run
https://github.com/scylladb/cpp-rs-driver/actions/runs/25594930991, the
build job successfully built the integration test binary but failed to
save it to the GitHub Actions cache (transient cache service timeout).
The test jobs then silently proceeded without the binary, and
build-integration-test-bin-if-missing attempted to rebuild from source
without build dependencies (libuv) installed, producing an unrelated
CMake error that was difficult to diagnose.

Set `fail-on-cache-miss: true` on the cache restore steps so that test
jobs fail immediately with a clear error when the binary is not
available, instead of falling through to a doomed rebuild attempt.

Author: wprzytula

.github/workflows/build-lint-and-test.yml

@@ -125,6 +125,11 @@ jobs:
         with:
           path: ${{ env.INTEGRATION_TEST_BIN }}
           key: ${{ env.INTEGRATION_TEST_BIN_CACHE_KEY }}
+          # Otherwise the binary won't be present, and test workflows will attempt to build it,
+          # failing due to build dependencies not being installed in the test workflow.
+          # It's better to fail early; this is a transient error that can be fixed by re-running
+          # the build-lint-and-unit-test job.
+          fail-on-cache-miss: true
 
       - name: Prepare environment
         run: make update-rust-tooling prepare-integration-test
@@ -213,6 +218,11 @@ jobs:
         with:
           path: ${{ env.INTEGRATION_TEST_BIN }}
           key: ${{ env.INTEGRATION_TEST_BIN_CACHE_KEY }}
+          # Otherwise the binary won't be present, and test workflows will attempt to build it,
+          # failing due to build dependencies not being installed in the test workflow.
+          # It's better to fail early; this is a transient error that can be fixed by re-running
+          # the build-lint-and-unit-test job.
+          fail-on-cache-miss: true
 
       - name: Prepare environment
         run: make update-rust-tooling prepare-integration-test