[ci] add missing deps in ml build file (ray-project#41906)

Signed-off-by: Lonnie Liu <[email protected]>

.buildkite/ml.rayci.yml

@@ -86,7 +86,7 @@ steps:
         --parallelism-per-worker 3
         --except-tags soft_imports,gpu_only,rllib,multinode
         --test-env=AIR_VERBOSITY=1
-    depends_on: mlbuild
+    depends_on: [ "mlbuild", "forge" ]
 
   - label: ":train: ml: tune soft import tests"
     tags: tune
@@ -95,7 +95,7 @@ steps:
       - bazel run //ci/ray_ci:test_in_docker -- //python/ray/tune/... ml
         --only-tags soft_imports 
         --build-name oss-ci-base_build
-    depends_on: oss-ci-base_build
+    depends_on: [ "oss-ci-base_build", "forge" ]
 
   - label: ":train: ml: air tests"
     tags: ml