feat: display Tempo icons and assets

[struong]

Description

Add Tempo testnet network icons and assets to MetaMask extension.

• Add TEMPO_TESTNET chain ID for network identification
• Display Tempo network icon in the extension

Changelog

CHANGELOG entry: Added Tempo testnet network icon and assets

Related issues

Fixes:

Manual testing steps

1. Build the extension with yarn start
2. Add Tempo testnet network (Chain ID: 0xa5bd)
3. Verify the Tempo network icon displays correctly in the network selector

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

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[cursor]

Missing native token image registration for Tempo testnet

Low Severity

The TEMPO_TESTNET chain is added to CHAIN_ID_TO_NETWORK_IMAGE_URL_MAP for network icons, but not to CHAIN_ID_TOKEN_IMAGE_MAP which is used for native token images in components like the asset picker. Other similar testnets (e.g., MONAD_TESTNET, SOPHON_TESTNET, MEGAETH_TESTNET) are registered in both maps. This omission could cause the native token image to be missing/undefined when displaying Tempo testnet assets.