ns-select. Fix XSS in #_setText()

https://github.com/yandex-ui/nanoislands/commit/63aaf009ae1eed877a74cdf1ee2ef571a421b2f8#diff-15f5941e4c6bf5e2882fd219266ca137R268 reopens XSS in nb-select fixed by 1fd58407b7bcbafb2e6e95232a13e39a336d8a34