feat(gov): support v1.Proposal in v1beta1.Proposal.Content (backport #14347)

[robert-zaremba]

Description

backport #14347

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Author Checklist

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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
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Reviewers Checklist

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• confirmed the correct type prefix in the PR title
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• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[robert-zaremba]

removed for loop here as well.

[julienrbrt]

removed for loop here as well.

Cool, can you do a quick pr for cleaning up main too?

[robert-zaremba]

Cool, can you do a quick pr for cleaning up main too?

Done,

thanks for swift review @julienrbrt