Halo: always pick "credential" execution method by default

[icedevml]

Description

Historically, the detectMethod() function was prioritizing the choice of WebNFC execution method as a default method if it was available on the current platform. This PR will change that in order to always use the "credential" execution method, since its general UX has improved a lot in the meantime.

Checklist

Changes to the drivers

• (PR Author) The affected drivers were manually tested

Changes to CLI

• (PR Author) The change was manually tested with the CLI
• (PR Author) The affected CLI features are working with the standalone binary (at least one platform)
• (Checked by maintainer) The CLI test procedure was run by the project's maintainer

Changes to web library

• (PR Author) The change was manually tested with the web library included within a classic HTML application (flat libhalo.js)
• (PR Author) The change was manually tested with the web library included within an app based on frontend framework (React.js or similar based on webpack)
• (Checked by maintainer) The web test suite was run by the project's maintainer

Changes to nfc-manager driver

• (PR Author) The change was manually tested in React Native app
• (Checked by maintainer) The test suite was run through the test React Native project