refactor: fetch notifications over graphql query

packages/backend/src/graphql/schema.graphql

@@ -46,6 +46,7 @@ type Query {
   getPermissionCatalog: PermissionCatalog
   getRole(id: String!): Role
   getRoles: [Role]
+  getNotifications: [Notification]
   getSamlAuthProvider: SamlAuthProvider
   getSamlAuthProviderRoleMappings(id: String!): [SamlAuthProvidersRoleMapping]
   getSubscriptionStatus: GetSubscriptionStatus
@@ -787,6 +788,13 @@ input UpdateAppAuthClientInput {
   active: Boolean
 }
 
+type Notification {
+  name: String
+  createdAt: String
+  documentationUrl: String
+  description: String
+}
+
 schema {
   query: Query
   mutation: Mutation