[lib] Handle use_new_flow for Identity V1 logout

Summary:
Address ENG-9710.

When received such Identity response, we should:

• Send logout message to primary device
• Display version unsupported modal (done in later diffs)

Depends on D14033

Test Plan:
Two devices: active primary and secondary

• In secondary device code: Commented the actual logout call and mocked the use_new_flow response.
• Logged out.
• Observed that primary device receiving the message and updating the device list

Reviewers: kamil, varun

Reviewed By: kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D14034