Add a testnet toggle to the network settings inside wallet settings

[seanstrom]

Feature Issue

User Story

As a user,
I want to be able to enable and disable the testnet mode from the network settings inside the wallet settings.

Description

Implement the testnet mode UI toggle for displaying the testnet banner globally through the app.

Designs

Figma flow: the Figma designs

Notes

The designs for disabling the testnet mode have a different background compared to the other screenshots. This is okay, the important piece to implement is the bottom-sheet view for the confirmation to disable the testnet mode.

Acceptance Criteria

Screen	Description
	Users can choose to view the network settings (inside wallet settings) by pressing on the "Network settings" menu button.
	Users should be able to see the Testnet mode UI toggle and enable Testnet mode by pressing on the UI toggle.
	Users are required to confirm that they want to enable Testnet mode by pressing on the Testnet mode UI toggle.
	Users are able to see that Testnet mode is enabled because the Testnet mode UI toggle is activated. And users should see the current Testnet mode status for each wallet network
	Users are required to confirm that they want to disable Testnet mode after pressing on the active Testnet mode UI toggle.