Sanitize Private Key with a trailing newline if none exists

[niieani]

A private key must be trailed by a newline, otherwise it will incorrectly prompt for a passphrase.
While copying and pasting the private key via the GUI it's easy to omit the trailing enter and scratch your head thinking: why won't Semaphore connect to your hosts?
There should be some built-in sanitization on the private key field that would add the trailing enter, if missing.

[niieani]

In fact, what I'm seeing is the opposite behavior - the key seems to be sanitized the wrong way by trimming the trailing whitespace, instead of adding it, causing SSH unable to connect with a ed25519 key. Adding the trailing newline manually fixes the problem temporarily, but Semaphore recreated the key with every start of the task. :/

[niieani]

A workaround for now is to trail the private key with two newlines and put some character afterwards (it will be ignored by SSH).