fix: address getting for cosmos chains with null info

[arlert-armin]

Summary

This PR fixes an issue where users were unable to generate addresses for certain Cosmos chains (e.g. Rune) when using wallets like Cosmostation, Keplr, and Leap.

The problem was caused by the experimental-chain detection logic. We were first checking for the existence of chain.info, and then reading info.experimental. For some chains, info can be null, which caused them to be incorrectly treated as experimental and blocked from address generation.

This change updates the logic to assume chains with info === null are non-experimental, and only treat a chain as experimental when info.experimental === true.

Fixes # (issue)

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How did you test this change?

• Verified address generation for chains with info === null (e.g. Rune)
• Confirmed existing behavior remains unchanged for chains explicitly marked as experimental
• Tested wallet integrations with Cosmostation, Keplr, and Leap to ensure addresses are returned correctly

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Implemented a user interface (UI) change, referencing our Figma design to ensure pixel-perfect precision

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