chore(kanban): removed unused import in sample

Author: tishko0

src/app/interactions/drag-drop/kanban-sample/kanban-sample.component.ts

@@ -1,6 +1,6 @@
 /* eslint-disable no-shadow */
 /* eslint-disable @typescript-eslint/naming-convention */
-import { ChangeDetectorRef, Component, ElementRef, OnInit, Renderer2, viewChild, ViewChild } from '@angular/core';
+import { ChangeDetectorRef, Component, ElementRef, OnInit, Renderer2, ViewChild } from '@angular/core';
 import { IDropBaseEventArgs, IDropDroppedEventArgs } from 'igniteui-angular';
 
 enum state {