Protect bundle burn from adding assets with zero amount

[dmidem]

This pull request addresses a specific part of a three-point task:

1. Prevent the burning of assets with zero value.
2. Prevent the burning of the same AssetBase more than once in a single transaction.
3. Prevent the burning of native assets.

For points 2 and 3, the existing add_burn function in the bundle already prevents duplications and burning of native assets:

• The function stores burns in a HashMap using the asset base as a key, preventing duplicate entries. If add_burn is called with an existing asset, its value gets added to the existing value, rather than creating a duplicate entry.
• In addition, add_burn already verifies if the added asset is native and returns an error if that's the case, disallowing the burning of native assets.

This pull request addresses the first point: disallowing the burning of assets with zero value, a check that was previously missing.

[what-the-diff]

PR Summary

• Added non-zero value check for burning
  Implemented a check to ensure that the value being burned is always greater than zero.

• Updated tests for the new behavior
  Adjusted tests to accommodate the new change in behavior, ensuring correct functionality.