test(ecocredit): add buy scenario to integration test

[technicallyty]

Description

• adds a buydirect scenario to the scenario test

Closes: n/a

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Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #1079 (26b2741) into master (334885c) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1079      +/-   ##
==========================================
+ Coverage   68.25%   68.27%   +0.02%     
==========================================
  Files         212      211       -1     
  Lines       21255    21308      +53     
==========================================
+ Hits        14507    14548      +41     
- Misses       5422     5428       +6     
- Partials     1326     1332       +6     

Flag	Coverage Δ
experimental-codecov	68.27% <100.00%> (+0.11%)	⬆️
stable-codecov	?

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[ryanchristo]

Pre-approving.