doc: remove the `ViewEncapsulation` import
doc: remove the `ViewEncapsulation` import

It is not used by the example code
shlomiassaf/angular2-modal,shlomiassaf/angular2-modal,shlomiassaf/ngx-modialog,shlomiassaf/ngx-modialog,shlomiassaf/angular2-modal,shlomiassaf/ngx-modialog,shlomiassaf/angular2-modal