Corregir error de compilación al Actualizar de angular 9 a angular 11

* El servicio es solo por corregir el error que sale en el frontend. * La aplicación recién esta en proceso de desarrollo, solo tiene desarrollado el menu. Al momento que actualice el proyecto de angular 9 a 11 el app ya no compila y me sale el siguiente error: Error: src/app/shared/services/ layout.service.ts:63:55 - error TS2729: Property 'defaultNavbar' is used before its initialization. 63 private dfNavbar = new BehaviorSubject<string>(this.defaultNavbar); ~~~~~~~~~~~~~ src/app/shared/services/layout.service.ts:25:10 25 public defaultNavbar: string; // Value Should be 'expended', 'collapsed', 'offcanvas', 'compact' ~~~~~~~~~~~~~ 'defaultNavbar' is declared here. Src/app/shared/services/layout.service.ts:66:54 - error TS2729: Property 'toggleNavbar' is used before its initialization. 66 private tNavbar = new BehaviorSubject<string>(this.toggleNavbar); ~~~~~~~~~~~~ src/app/shared/services/layout.service.ts:26:10 26 public toggleNavbar: string; // Value Should be 'expended', 'collapsed', 'offcanvas', 'compact' ~~~~~~~~~~~~ 'toggleNavbar' is declared here. Src/app/shared/services/layout.service.ts:69:55 - error TS2729: Property 'navBarEffect' is used before its initialization. 69 private nvEffect = new BehaviorSubject<string>(this.navBarEffect); ~~~~~~~~~~~~ src/app/shared/services/layout.service.ts:27:10 27 public navBarEffect: string; // Value Should be 'shrink', 'push', 'overlay' ~~~~~~~~~~~~ 'navBarEffect' is declared here. Src/app/shared/services/layout.service.ts:93:60 - error TS2729: Property 'deviceType' is used before its initialization. 93 private appDeviceType = new BehaviorSubject<string>(this.deviceType); ~~~~~~~~~~ src/app/shared/services/layout.service.ts:28:10 28 public deviceType: string; // Value should be mobile, tablet, desktop ~~~~~~~~~~ 'deviceType' is declared here.