[LSC] Add LOCAL_LICENSE_KINDS to pdk

Added SPDX-license-identifier-Apache-2.0 to:
  apps/HelloPDK/Android.mk
  apps/TestingCamera/Android.mk
  apps/TestingCamera2/Android.mk

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all

Exempt-From-Owner-Approval: janitorial work
Change-Id: Iad325602c75f37417856edbc0c9c28dc42079b14