adding changes for burn functionality on spread fee

[muku314115]

Summary of changes

Report of required housekeeping

• [ ] Github issue OR spec proposal link
• [ ] Wrote tests
• [ ] Updated API documentation (client/lcd/swagger-ui/swagger.yaml)
• [ ] Added a relevant changelog entry: clog add [section] [stanza] [message]

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(FOR ADMIN) Before merging

• [ ] Added appropriate labels to PR
• [ ] Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)
• [ ] Confirm added tests are consistent with the intended behavior of changes
• [ ] Ensure all tests pass