Abstract WalletConnectSDK to make it testable
Implement WC service pairing test
Bring back DAppsWorkflow tests back to life and add a pair modal test
Updates: #14927
Implement the initial Pairing user workflow and disconnect option for
the first session.
Also
- rename pairing modal accordingly (`PairWCModal.qml`) to make room for the proper
`ConnectDAppModal.qml`
- basic tests for service helpers
- update storybook to reflect the new user workflows
Closes#14607