Add CTA for Developers to Update FCL In Testnet Discovery UI

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Problem

It has historically been difficult to ensure FCL updates are promptly propogated throughout the ecosystem. Developers are often using versions of FCL that are outdated and missing many bug fixes, UX improvements, or new features. They are often unaware of this.

Solution

Add a CTA in Testnet FCL Discovery for devs to update to latest FCL version, if outdated.

Context

Blocked by Metrics of FCL Version Usage