[BD-3978] Add instructions on how to test the Web SDK Content Cards using browser dev tools

[zairro]

Why are you making this change? (required)

On the Content Cards page, there previously didn't exist instructions on how to test the Web SDK's integration with Content Cards. This PR introduces new content that includes a set of instructions explaining how to use the browser's dev tools to test out Content Cards for the Web SDK.

Related PRs, issues, or features (optional)

• BD-3978

Feature release date (optional)

• N/A

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[Copilot]

Pull request overview

Adds a new documentation section to help developers validate their Web SDK Content Cards integration using browser developer tools, filling a gap in the existing Web Content Cards guide.

Changes:

• Added a “Testing Content Cards” section with step-by-step instructions for verifying Content Cards via the browser console.
• Included example console commands intended to help confirm cards are available / UI can be displayed.

[christorbraze]

This looks correct to me, but probably still want a ✅ from the web-sdk team