Sort files in sdk snapshot zip to ensure consistent behavior

The order of the files in the sdk snapshot was stable but depended on
how the sdk was built. If the snapshot was created directly then the
files have one order, if it was created by merging in files from other
zips then it has a different order.

This change ensures files are in alphabetical order no matter how the
snapshot zip is constructed.

Bug: 232401814
Test: m media-module-sdk
      # Check the contents of the following zips to ensure that they are sorted
      # after this change.
      # out/soong/.intermediates/packages/modules/Media/apex/media-module-sdk/common_os/media-module-sdk-current.unmerged.zip
      # out/soong/mainline-sdks/media-module-sdk-current.zip
Change-Id: Ie97e0119c07a1f34a2b1d3ea6895f0e76cd195a8