Update SessionsController's create action to send all the initial props to the Miru desktop app as login response

[sanjibroy360]

What

• Update SessionsController's create action to send all the initial props to the Miru desktop app as login response and also added specs for this change.
• It'll send the initial props as a response only when it has the ?app=miru_desktop param otherwise it'll send the regular login response.

Why

• To get the avatar_url and other initial props on the Miru desktop app as well.

[prasanthchaduvula]

@sanjibroy360 Let me test this out and will get back to you

[prasanthchaduvula]

@sanjibroy360 I went through the changes and will try to push a change to avoid the skipping of skip_before_action :verify_authenticity_token, only: :create