Fix dev-only lint errors in delegation packages

[mcmire]

Explanation

Currently, there are some type errors that exist in packages owned by @MetaMask/delegation. These type errors are not present in production code, so they are not flagged by yarn build, but they will be flagged soon by yarn lint:tsc, and so we need to fix them.

References

https://consensyssoftware.atlassian.net/browse/WPC-1275

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Low Risk
Test-only type annotations with no runtime or production code changes.

Overview
Addresses upcoming yarn lint:tsc failures in delegation-owned packages by tightening types in tests only—no production behavior changes.

In GatorPermissionsController.test.ts, mock delegation objects passed to encodeDelegations now assert delegate, delegator, and caveat args as Hex, matching stricter delegation typing.

In decodePermission/utils.test.ts, the all-zero expiry caveat terms fixture is annotated so it satisfies the Hex parameter expected by extractExpiryFromCaveatTerms.

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