Add ability to create contact points for existing integration from Oncall UI

[Konstantinov-Innokentii]

Currently "Create new contact point" for alerting integration button is opening Alerting UI. After creation of contact point there integration page refresh is required to fetch new contact point so it will be available in the existing contact points dropdown.
I propose to unify that experience with the creation of integration, where contact point could be created from oncall ui.