Reverts: Downgrade to tm v0.34.21

[Manav-Aggarwal]

Description

Downgrades tendermint to 0.34.21 since Tendermint v0.35 got dropped

Closes: #269

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Author Checklist

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I have...

• [x] included the correct type prefix in the PR title
• [x] added ! to the type prefix if API or client breaking change
• [x] targeted the correct branch (see PR Targeting)
• [x] provided a link to the relevant issue or specification
• [x] followed the guidelines for building modules
• [x] 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

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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)

[Manav-Aggarwal]

everything is moved to cosmos-sdk-rollmint repo