Improve type safety by applying `satisfies` operator

[MajorLift]

The next version bump for TypeScript in core and metamask-module-template will mark an update to version 4.9, which will make the satisfies operator keyword available for use (https://devblogs.microsoft.com/typescript/announcing-typescript-4-9/#satisfies).

The satisfies operator is a safer alternative to type annotations (val: T) and type assertions (val as T). We should investigate opportunities to improve type safety in the codebase by applying this feature to existing code.