Update Testnet migration warning banner's text & Add bridge warning

[gtg7784]

Pull Request Summary

Describe what changes this pull request makes to the repository

Check list

• [ ] contains breaking changes
• [ ] adds new feature
• [x] modifies existing feature (bug fix or improvements)
• [ ] relies on other tasks
• [ ] documentation changes
• [ ] tested on mobile devices

This pull request makes the following changes:

Changes

• update testnetSwitchWarning content to We have switched our zkEVM testnet to zKyoto from zKatana. zKatana will no longer available.

To-dos

*Feel free to remove this section if it's not applicable

• [ ] (ex: add user list)

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 068feed):

https://astar-apps--pr1244-fix-testnet-warning-6y8cz649.web.app

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[gtg7784]

Adds

• navite bridge high traffic modal
• navite bridge high traffic warning textbox