Happy Number Implementation

[itsAkshayDubey]

Hi,
I have not seen any implementation of Happy Number in this repo.
Could you please assign this issue to me?

[siriak]

They are implemented here https://github.com/TheAlgorithms/Java/blob/e488b7b5bb3f7c48591d084bbd5e12674df362f9/src/main/java/com/thealgorithms/others/HappyNumbersSeq.java