refactor(web): remove unnecessary `getResourcePath` dependency on `DeviceSpec`

See the changes at lines 1404 - 1408 - they're needed to complete the requirements of the `DeviceSpec` type needed for the `.hostDevice` field of `getResourcePath`'s parameter.

Alternatively, we _could_ mock it out with `null`, but that could become prone to breakage. Or we could rework the `getResourcePath` method to use just `pathConfig`.

_Originally posted by @jahorton in https://github.com/keymanapp/keyman/pull/16136#discussion_r3492793484_

Start at lines 1404–1408 and trace getResourcePath, its pathConfig parameter, and the DeviceSpec requirement for hostDevice. Compare the existing dependency with the null-mocking and pathConfig-only alternatives; done means getResourcePath no longer requires an unnecessary DeviceSpec while preserving its current behavior.

Written by the indexing model from the issue text.