Add comment to AndroidManifest

- Wi-Fi result data will only be returned from WifiDialogActivity if the
calling package has location permission.

Test: add comment only, no test required.
Bug: 185126813

Merged-In: I81c4d801c4ee211f43a1688a62daaff3b47eae1a
Change-Id: I81c4d801c4ee211f43a1688a62daaff3b47eae1a
(cherry picked from commit 56a88885)