chore(toolbar): add ngTemplateContextGuard for the toolbar (#12085)

Co-authored-by: Martin Dragnev <[email protected]>

Author: dkamburov

projects/igniteui-angular/src/lib/grids/toolbar/common.ts

@@ -66,4 +66,9 @@ export interface IgxGridToolbarTemplateContext {
 @Directive({ selector: '[igxGridToolbar]'})
 export class IgxGridToolbarDirective {
     constructor(public template: TemplateRef<IgxGridToolbarTemplateContext>) {}
+
+    public static ngTemplateContextGuard(_dir: IgxGridToolbarDirective, 
+        ctx: unknown): ctx is IgxGridToolbarTemplateContext { 
+        return true
+    };
 }