RecastNavmesh contents are non-deterministic across navmesh builds

Per-tile data such as TileIndex and salt are stored non-deterministically.

1. Create a new level using the Open World template.
2. Place a NavMeshBoundsVolume and adjust its size.
3. Save the level and confirm that RecastNavMesh-Default has been saved.
4. Select RecastNavMesh-Default in the Outliner.
5. Right-click menu > Copy Selected Actor(s) File Path to confirm the file location.
6. In Windows Explorer, copy the file to create a backup for comparison.
7. Run Build Paths in the editor and re-save RecastNavMesh-Default.
8. Perform a binary comparison between the newly saved file and the backup saved at step 6.

Result:

The file differs on every build.