chore: x/feegrant audit changes

[atheeshp]

Description

ref: #16508

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Author Checklist

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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

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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)

[julienrbrt]

I think protos should have been re-generated.

[julienrbrt]

@Mergifyio backport release/v0.50.x

[mergify]

backport release/v0.50.x

✅ Backports have been created

• #16664 chore: x/feegrant audit changes (backport #16652) has been created for branch release/v0.50.x