Reset the State machines(Request and Scan) when User changes screen

[tilak-puli]

As State machines are not reset on screen change following issues are happening.

1. Clicking on icon in bottom nav bar, while staying in same screen causing screen to become white.
   -- for example, Go to Scan screen, scan the QR code. Once the Sharing Card screen is rendered in the UI Click on Scanner Icon in bottom navbar the Screen becomes white.
2. Start the VC transfer and on Verifier side, Go to Home Screen. Wallet will be still connected. Wallet gets disconnected only when User comes back to request screen or scan screen.

Suggested Solution

On Screen change, Reset the state machine.

Screenshots for the issue:

Click on the scanner icon when we are on Sharing Card Screen

The screen becomes white