[ENG-3567] fix: workaround for hiro api 429s on testnet while changing btc

[teebszet]

🔘 PR Type

• [x] Bugfix

📜 Background

Provide a brief explanation of why this pull request is needed. Include the problem you are solving or the functionality you are adding. Reference any related issues.

Issue Link: #[issue_number] Context Link (if applicable):

🔄 Changes

• fix: skip server validation of api urls if value didn't change
• and skip reset of form if selecting an already selected network (testnet/mainnet)
• and don't display the x button for clearing if input is empty

🖼 Screenshot / 📹 Video

https://github.com/secretkeylabs/xverse-web-extension/assets/6109710/bc935e17-7383-4a15-98b9-897d9ea3c53b

✅ Review checklist

Please ensure the following are true before merging:

• [ ] Code Style is consistent with the project guidelines.
• [ ] Code is readable and well-commented.
• [ ] No unnecessary or debugging code has been added.
• [ ] Security considerations have been taken into account.
• [ ] The change has been manually tested and works as expected.
• [ ] Breaking changes and their impacts have been considered and documented.
• [ ] Code does not introduce new technical debt or issues.