feat: adjusting the 'add network screen' in network bottom sheet, for network UI redesign

[EtherWizard33]

Description

This PR shows the 'Add custom network' form directly after clicking the button, where the user can add and connect to a custom network. A demo can be viewed here: https://www.loom.com/share/bd380aca1065428ea584b0421ce69fb9

Here is a link to the figma: https://www.figma.com/design/76R5BvAVubUhWaN2Ld7MAv/Default-Networks?node-id=1303-34400&m=dev

Related issues

Ensures that the form is displayed directly after clicking since the list of popular networks are now integrated in the list.

Manual testing steps

1. From the home page, click the network selector at the top of the screen, a bottom sheet comes up with a list of networks
2. At the bottom of the bottom sheet, click Add custom network button, a form should show up allowing to add a network
3. Fill the form with relevant information and add the network

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[bot]]

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[salimtb]

work as expected , good job !

[sonarcloud[bot]]

Quality Gate passed

Issues
5 New issues
0 Accepted issues

Measures
0 Security Hotspots
50.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud