Add unit test for mixed items OR rule as documentation

[johnnyshankman]

This PR

I found it unclear what is expected for the scenario I've outlined in this unit test:

AND STEP 0:
  BURN 3x of any token on some 1155 contract
     OR
  BURN 1x of someERC721
AND STEP 1:
  BURN 1x of token id 2 on some 1155 contract

the answer is that the 1155 token is not repeated 3 times in burn tokens, instead it is added just one and mapped to the burn item that has amount set to 3x.

Self-Review

• Review and comment PR file changes
• Description provides context for the changes
• Tests are included for the PR (required on server changes)

[github-actions]

LCOV of commit dbd7b01 during Test! #439

Summary coverage rate:
  lines......: 55.3% (1573 of 2846 lines)
  functions..: 59.5% (238 of 400 functions)
  branches...: 37.3% (301 of 807 branches)

Files changed coverage rate: n/a