Drop superfluous cargo build step

.. as we're about to `cargo test` anyways.

Author: tnull

.github/workflows/vss-integration.yml

@@ -44,5 +44,4 @@ jobs:
         run: |
           cd ldk-node
           export TEST_VSS_BASE_URL="http://localhost:8080/vss"
-          RUSTFLAGS="--cfg vss_test" cargo build --verbose --color always
           RUSTFLAGS="--cfg vss_test" cargo test --test integration_tests_vss