refactor: `BinaryToOctal` (#5338)

* refactor: BinaryToOctal

* checkstyle: fix formatting

* refactor: adding input correctness case, cover by tests. Renaming variable

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Co-authored-by: alxkm <alx@alx.com>
Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>