These attributes converting to ng-reflect-{attributeName} in browser, so jasmine need to look for that attribute. The test below should work.
it('kendo-grid element should contain resizable attribute with "true" value', () => {
const element = fixture.debugElement.query(By.css('kendo-grid'));
expect(element.nativeElement.getAttribute('ng-reflect-resizable')).toBe('true');
});