fix: remove Partial from Dependency type

[dword-design]

Currently the Dependency type is a partial of Record<string, string>, which allows { 'type-fest': undefined }.

Tests are failing but I think they are not related.

[som-sm]

This PR makes sense because undefined should not be allowed as a valid value. undefined should only come up while accessing an unknown property from an index signature, which can be enforced using noUncheckedIndexedAccess compiler option.

// @noUncheckedIndexedAccess: true
declare const x: {[x: string]: number};

const y = x.foo;
//=> number | undefined

// @ts-expect-error
x.bar = undefined; // Not allowed

But all instances of Partial<Record<... need fixing, not just Dependency.

Also, the failing tests are related to this change, so tests need to be updated as well.