Clarify documentation for getActiveNetworkInfo and friends

For VPNs it's unobvious what these methods do, so document that.

Bug: 70917007
Test: Comment changes only. Checkdoc passes.
Change-Id: I31ec1aea356d88d969eaf9fc7d8c2ed13ce924eb
1 file changed
tree: ac63f1e8c952afefc40737139f1ff5b7cb833bd2
  1. core/
  2. services/
  3. tests/