Lite bugreports(wifi/telephony) don't need screenshots

Set do_fb to false for lite bugreports to not take screenshots.

Also, add a nonempty check for screenshot files before broadcasting to
notification. This way while sharing or uploading to drive/gmail by
clicking the "Share" button would not show empty file (Not able to
upload) error.

Update unit tests to check for do_fb set to false for wifi/telephony.

Bug: 128546970
Test: Manually take a wifi bugreport:
    * adb root
    * adb shell setprop dumpstate.options bugreportwifi
    * adb shell dumpstate
    * share bugreport from the notification to the drive
    * No upload failures (previously screenshot would show "Upload was
    unsuccessful" notification.)
Test:
    * adb shell mkdir /data/nativetest64
    * mmm -j frameworks/native/cmds/dumpstate/ &&
      adb push ${OUT}/data/nativetest64/dumpstate_test* /data/nativetest64
      && adb shell /data/nativetest64/dumpstate_test/dumpstate_test &&
      printf "\n\n#### ALL TESTS PASSED ####\n"

Change-Id: I0d2fe2a64f91dee7d090d5f8353e86d51ed5fb94