fix(date-picker): remove deprecation warning for the label property. #8917 (#8937)

Author: valadzhov

projects/igniteui-angular/src/lib/date-picker/date-picker.component.html

@@ -8,7 +8,7 @@
         <igx-prefix>
             <igx-icon>today</igx-icon>
         </igx-prefix>
-        <label *ngIf="labelVisibility&&!_labelDirectiveUserTemplate" igxLabel>{{label}}</label>
+        <label *ngIf="labelVisibility&&!_labelDirectiveUserTemplate" igxLabel>{{labelInternal}}</label>
         <input
             class="igx-date-picker__input-date"
             igxInput
@@ -27,7 +27,7 @@
         <igx-prefix (click)="onOpenClick($event)">
             <igx-icon>today</igx-icon>
         </igx-prefix>
-        <label *ngIf="labelVisibility&&!_labelDirectiveUserTemplate" igxLabel>{{label}}</label>
+        <label *ngIf="labelVisibility&&!_labelDirectiveUserTemplate" igxLabel>{{labelInternal}}</label>
         <input
             class="igx-date-picker__input-date"
             igxInput

projects/igniteui-angular/src/lib/date-picker/date-picker.component.ts

@@ -182,7 +182,22 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
         <label igxLabel>Custom label</label>
     </igx-date-picker> `)
     @Input()
-    public label = 'Date';
+    public get label(): string {
+        return this._label;
+    }
+
+    public set label(v: string) {
+        this._label = v;
+    }
+
+    public get labelInternal() {
+        return this._label;
+    }
+
+    /** @hidden @internal */
+    public get labelTemplate(): IgxLabelDirective {
+        return this._labelDirectiveUserTemplate;
+    }
 
     /**
      * Gets/Sets the `IgxDatePickerComponent` label visibility.
@@ -459,7 +474,6 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
             displayData: this.displayData,
             format: this.format,
             isSpinLoop: this.isSpinLoop,
-            label: this.label,
             labelVisibility: this.labelVisibility,
             locale: this.locale,
             mask: this.mask,
@@ -784,6 +798,7 @@ export class IgxDatePickerComponent implements IDatePicker, ControlValueAccessor
     private _onOpen = new EventEmitter<IgxDatePickerComponent>();
     private _onClose = new EventEmitter<IgxDatePickerComponent>();
     private _ngControl: NgControl = null;
+    private _label = 'Date';
 
     //#region ControlValueAccessor