ci: remove 25.2 step

Author: RobPasMue

.github/workflows/backwards_compatibility.yml

@@ -43,8 +43,7 @@ jobs:
             backend-version: "24.2"
           - image-tag: "windows-25.1"
             backend-version: "25.1"
-          - image-tag: "core-windows-25.2"
-            backend-version: "25.2"
+
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with: