Enable visionos tests after GH runner update

PiperOrigin-RevId: 620965206

.github/workflows/test_objectivec.yml

@@ -68,11 +68,14 @@ jobs:
     strategy:
       fail-fast: false   # Don't cancel all jobs if one fails.
       matrix:
-        PLATFORM: ["ios", "macos", "tvos", "watchos"]
+        PLATFORM: ["ios", "macos", "tvos", "watchos", "visionos"]
         CONFIGURATION: ["Debug", "Release"]
         include:
           - OS: macos-12
             XCODE: "14.1"
+          - OS: macos-14
+            PLATFORM: "visionos"
+            XCODE: "15.2"
     name: CocoaPods ${{ matrix.PLATFORM }} ${{ matrix.CONFIGURATION }}
     runs-on: ${{ matrix.OS }}
     steps: