Add VirtualAuthenticator tests to Ruby examples

[tcannonfodder]

Description

• Added tests for the Ruby example project that verify & document the VirtualAuthenticator API
• Note that one test is failing; I wasn't able to figure out what incantation of Base64 decoding/encoding was necessary

Motivation and Context

• Adding these tests helps document how the Selenium library can be used with virtual authenticators

Types of changes

• Code example added (and I also added the example to all translated languages)

Checklist

• I have read the contributing document.
• I have used hugo to render the site/docs locally and I am sure it works.

[netlify]

👷 Deploy request for selenium-dev pending review.

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Name	Link
🔨 Latest commit	3126bdc

[CLAassistant]

All committers have signed the CLA.

[A1exKH]

LGTM.