fix(@angular-ru/flex-layout): support string type for flex-bottom-indent

Author: splincode

packages/flex-layout/src/directives/flex-bottom-indent.directive.ts

@@ -4,7 +4,9 @@ import { AbstractFlexLayoutDirective } from './abstract-flex-layout.directive';
 
 @Directive({ selector: '[flex-bottom-indent]' })
 export class FlexBottomIndentDirective extends AbstractFlexLayoutDirective implements AfterViewInit {
-    @Input('flex-bottom-indent') @HostBinding('style.margin-bottom.px') public bottomIndent: number | null = null;
+    @Input('flex-bottom-indent')
+    @HostBinding('style.margin-bottom.px')
+    public bottomIndent: string | number | null = null;
 
     constructor(protected readonly el: ElementRef) {
         super();