Ignore focal length test on external camera.

Bug: 110440069

Change-Id: I6991d4dcd353a5af7021de2c9b91a077df7dc477
diff --git a/tests/camera/src/android/hardware/camera2/cts/StillCaptureTest.java b/tests/camera/src/android/hardware/camera2/cts/StillCaptureTest.java
index 0ef1856..e77ad79 100644
--- a/tests/camera/src/android/hardware/camera2/cts/StillCaptureTest.java
+++ b/tests/camera/src/android/hardware/camera2/cts/StillCaptureTest.java
@@ -521,6 +521,10 @@
                     Log.i(TAG, "Camera " + id + " does not support color outputs, skipping");
                     continue;
                 }
+                if (mStaticInfo.isExternalCamera()) {
+                    Log.i(TAG, "Camera " + id + " is external, skipping");
+                    continue;
+                }
                 focalLengthTestByCamera();
             } finally {
                 closeDevice();