feat(coderd/notifications): group workspace build failure report (#17306)

Closes https://github.com/coder/coder/issues/15745

Instead of sending X many reports to a single template admin, we instead
send only 1.

coderd/database/dbmem/dbmem.go

@@ -3291,6 +3291,7 @@ func (q *FakeQuerier) GetFailedWorkspaceBuildsByTemplateID(ctx context.Context,
 		}
 
 		workspaceBuildStats = append(workspaceBuildStats, database.GetFailedWorkspaceBuildsByTemplateIDRow{
+			WorkspaceID:            w.ID,
 			WorkspaceName:          w.Name,
 			WorkspaceOwnerUsername: workspaceOwner.Username,
 			TemplateVersionName:    templateVersion.Name,