[ci] scope rust integration job to test_fluss target only

Author: fresh-borzoni

.github/workflows/build_and_test_rust.yml

@@ -84,7 +84,7 @@ jobs:
         uses: Swatinem/rust-cache@c19371144df3bb44fab255c43d04cbc2ab54d1c4 # v2.9.1
 
       - name: Integration Test
-        run: cargo test --features integration_tests --all-targets --workspace --exclude fluss_python --exclude fluss-cpp --exclude fluss_nif
+        run: cargo test --features integration_tests --test test_fluss -p fluss-rs
         env:
           RUST_LOG: DEBUG
           RUST_BACKTRACE: full