Update git submodules

* Update platform/packages/modules/NetworkStack from branch 'master'
  to bb2c43b7c9173673d6f29a569c90dcafc0cc9a4f
  - Merge "Add RECEIVER_EXPORTED flag to NetworkStack API Shims"
  - Add RECEIVER_EXPORTED flag to NetworkStack API Shims
    
    Android T adds support to allow a runtime receiver to be registered as
    not exported, but to ensure apps can take advantage of this, calls to
    registerReceiver must specify a flag indicating whether the receiver
    should be exported for apps targeting T+ that are registering for
    non-system broadcasts. This commit adds the RECEIVER_EXPORTED
    flag to the API shims for code or tests that require exporting
    a dynamic receiver.
    
    Bug: 217654947
    Test: atest HostsideRestrictBackgroundNetworkTests#testAppIdle_toast
    Change-Id: Ic7e621646db3b703bed905f01bbcf3adf22f5523