fix(schematics): fixed datepicker style path for schematics (#6445)

Author: SvetlanaMuravlova

src/schematics/src/ng-add/index.ts

@@ -27,7 +27,7 @@ const BOOTSTRAP_AVAILABLE_STYLES = {
 `]
 };
 const DATEPICKER_AVAILABLESTYLES = {
-  'css': [`./dist/ngx-bootstrap/datepicker/bs-datepicker.css`],
+  'css': [`./node_modules/ngx-bootstrap/datepicker/bs-datepicker.css`],
   'scss': [`
 /* Importing Datepicker SCSS file. */
 @import "node_modules/ngx-bootstrap/datepicker/bs-datepicker";