feat(files): Suspicious Sand and Gravel packs

[NSPC911]

Packs Added:

• Suspicious Sand and Gravel Borders
• Sus Sand and Gravel

Official Issues Fixed

• https://github.com/BedrockTweaks/Files/issues/32
• https://github.com/BedrockTweaks/Files/issues/59

By checking the following boxes with an X, you ensure that:

• [x] The pack was tested ingame in at least one device.

• [x] The pack is an existing BT pack, is a missing pack from VT or is an accepted pack/change in a discussion.

• [x] The pack code follows the style guide.

• [x] The commits follow the contribution guidelines.

• [x] The PR follows the contribution guidelines.

• [x] (Optional) Tested in Windows

• [x] (Optional) Tested in Android

• [ ] (Optional) Tested in iOS

• [ ] (Optional) Tested in any console

• [ ] (Optional) Tested in BDS