Make Tethering file NetworkRequests only if needed. am: 2bcde0fd97 am: cce64f0dd7 am: bd868cd5d0

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1556199

Change-Id: I5e1059993a86ec1fdd5bb9a7001683af5dcd6b57
tree: 03ddbbe919a74dc4aaef06254502340efa873259
  1. tests/
  2. Tethering/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING