[Android 16] Update linux_android_emu_unstable to use avd rev 7 (flutter#177854)

Updated `linux_android_emu_unstable` configs to use the [latest
build_id](https://chrome-infra-packages.appspot.com/p/chromium/tools/android/avd/linux-amd64/+/build_id:8699815938758639089)
with rev 7.

Will audit if test targets pass on rev 7. Expecting
`android_engine_vulkan_tests` to be flaky and the rest to pass.

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Author: jesswrd

.ci.yaml

@@ -73,7 +73,7 @@ platform_properties:
         [
           {"dependency": "android_sdk", "version": "version:36v4"},
           {"dependency": "android_virtual_device", "version": "android_36_google_apis_x64.textpb"},
-          {"dependency": "avd_cipd_version", "version": "build_id:8719362231152674241"},
+          {"dependency": "avd_cipd_version", "version": "build_id:8699815938758639089"},
           {"dependency": "open_jdk", "version": "version:21"}
         ]
       os: Ubuntu
@@ -1688,6 +1688,19 @@ targets:
       - engine/**
       - DEPS
 
+  - name: linux_android_emu_unstable android_engine_vulkan_tests
+    recipe: flutter/flutter_drone
+    bringup: true
+    timeout: 60
+    properties:
+      shard: android_engine_vulkan_tests
+      tags: >
+        ["framework", "hostonly", "shard", "linux"]
+      dependencies: >-
+        [
+          {"dependency": "goldctl", "version": "git_revision:2387d6fff449587eecbb7e45b2692ca0710b63b9"}
+        ]
+
   - name: Linux_android_emu_vulkan_stable android_engine_vulkan_tests
     recipe: flutter/flutter_drone
     bringup: true