Fix jit-kernel unit test CI dependency install in pr-test workflow (#21089)

.github/workflows/pr-test.yml

@@ -682,7 +682,7 @@ jobs:
       - name: Install dependencies
         timeout-minutes: 20
         run: |
-          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh diffusion
+          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} bash scripts/ci/cuda/ci_install_dependency.sh diffusion
 
       - name: Run sgl-kernel unit tests on B200
         timeout-minutes: 30
@@ -745,7 +745,7 @@ jobs:
       - name: Install dependencies
         timeout-minutes: 20
         run: |
-          bash scripts/ci/cuda/ci_install_dependency.sh
+          bash scripts/ci/cuda/ci_install_dependency.sh diffusion
 
       - name: Run test
         timeout-minutes: 30
@@ -847,8 +847,6 @@ jobs:
       )
     runs-on: 1-gpu-5090
     timeout-minutes: 240
-    env:
-      IS_BLACKWELL: "1"
     steps:
       - name: Checkout code
         uses: actions/checkout@v4