feat: add gravity chain logo svg

[oyyblin]

Description

Add Gravity Alpha Mainnet and Testnet svg logo

Related issues

Fixes:

Manual testing steps

1. Go to add network
2. Add gravity networks

• gravity networks should have logo

Screenshots/Recordings

Pre-merge author checklist

• I’ve followed MetaMask 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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[oyyblin]

I have read the CLA Document and I hereby sign the CLA