[AC-358] SelfHosted update subscription page (#5101)

* [AC-358] Add selfHostSubscriptionExpiration property to organization-subscription.response.ts

* [AC-358] Update selfHost org subscription template

- Replace "Subscription" with "SubscriptionExpiration"
- Add question mark help link
- Add helper text for grace period
- Add support for graceful fallback in case of missing grace period in subscription response

* Update libs/common/src/billing/models/response/organization-subscription.response.ts

Co-authored-by: Thomas Rittson <31796059+eliykat@users.noreply.github.com>

* [AC-358] Remove unnecessary hypen

Co-authored-by: Thomas Rittson <31796059+eliykat@users.noreply.github.com>

* [AC-358] Introduce SelfHostedOrganizationSubscription view
- Encapsulate expiration/grace period logic in the new view object.
- Remove API response getters from the angular component
- Replace the API response object with the new view

* [AC-358] Clarify name for new expiration without grace period field

* [AC-358] Update constructor parameter name

* [AC-358] Simplify new selfhost subscription view

- Make expiration date properties public
- Remove obsolete expiration date getters
- Update the component to use new properties
- Add helper to component for determining if the subscription should be rendered as expired (red text)

* [AC-358] Rename isExpired to isExpiredAndOutsideGracePeriod to be more explicit

---------

Co-authored-by: Thomas Rittson <31796059+eliykat@users.noreply.github.com>

libs/common/src/billing/models/response/organization-subscription.response.ts

@@ -11,6 +11,7 @@ export class OrganizationSubscriptionResponse extends OrganizationResponse {
   subscription: BillingSubscriptionResponse;
   upcomingInvoice: BillingSubscriptionUpcomingInvoiceResponse;
   expiration: string;
+  expirationWithoutGracePeriod: string;
 
   constructor(response: any) {
     super(response);
@@ -24,5 +25,6 @@ export class OrganizationSubscriptionResponse extends OrganizationResponse {
         ? null
         : new BillingSubscriptionUpcomingInvoiceResponse(upcomingInvoice);
     this.expiration = this.getResponseProperty("Expiration");
+    this.expirationWithoutGracePeriod = this.getResponseProperty("ExpirationWithoutGracePeriod");
   }
 }