Fix Issue #2042: prevent invalid input alert on backspace in Armstrong Checker#2060

Euphoric-Coder wants to merge 1 commit intoTusharKesarwani:mainTusharKesarwani/Front-End-Projects:mainfrom

Euphoric-Coder:issue2042-fix-armstrong-invalid-inputEuphoric-Coder/Front-End-Projects:issue2042-fix-armstrong-invalid-inputCopy head branch name to clipboard