Merge "Guard the usage of PacProxyManager when it is not supported by the device." am: 76f61bb2e8

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2623371

Change-Id: I582fbe92042c4afab888a4e0fe2784481c0d9252
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>