chore: Enable Bitcoin testnets before BIP44

[aganglada]

Description

Enable Bitcoin testnets to be created through the Network selector
Due to dependecies on the BIP44 work, we are not addressing the network switching when Account changes (known issue until BIP44 stage 2 is ready).

Enable Bitcoin testnets

Changelog

CHANGELOG entry: Add Bitcoin testnet support.

Related issues

Fixes:

Manual testing steps

Feature: my feature name

  Scenario: user clicks on the Token "Network Selector"
    Given no account exist on the Bitcoin testnet scope
    Then it prompts the user to create a Testnet account

  Scenario: user clicks on the Token "Network Selector"
    Given an account exist on the Bitcoin testnet scope
    Then switches to the respective account

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile 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]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
92.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud