[FEATURE] Add a new-line linter in the current CI workflow

[owaiskazi19]

Is your feature request related to a problem?

Coming from opensearch-project/OpenSearch#2857. Add a new-line linter to make sure all files end with a single newline. This is a POSIX standard, read more https://stackoverflow.com/questions/729692/why-should-text-files-end-with-a-newline

What solution would you like?

Can use https://github.com/fernandrone/linelint/releases for the workflow.

What alternatives have you considered?

A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?

Add any other context or screenshots about the feature request here.

[dbwiddis]

This is trivially fixed by adding endWithNewline() to the formatting.gradle file (probably right after trimTrailingWhitespace())

[dbwiddis]

I don't like that the linter complains about it but doesn't fix it. Adding the line to spotless as suggested above would fix it (and also fail it on spotless check but with a more helpful message how to fix!)