Fix typo in Slack Callback plugin (#38268)
Fix typo in Slack Callback plugin (#38268)

`get_options` is an undefined method from CallbackBase

As a result, remove the trailing `s` letter.

Signed-off-by: Daniel Andrei Minca <632cd94f277d046f178d1dea6979a79f0d72d0f2@gmail.com>
thaim/ansible,thaim/ansible