closes#16831
Moving the dapp popups to the global scope in order for them to be triggered on any view.
There are a few changes required for this:
1. DAppsWorkflow has been split. Previously all popups were declared in the `DappsComboBox`. Now the DAppsWorkflow inherits the QObject instead and the `DappsComboBox` is used as is in the wallet header.
2. The DAppsWorkflow has been moved to AppMain. The DAppsWorkflow will be constructed in the scope of DAppsService and connected directly to the service signals
3. Updated tests and storybook with the new structure
4. Removed the `dAppsService` from `Global`. There's no reason to keep the `dAppsService` instance in the `Global` singleton.