[git_auth] Minor wording consistency fix

Make it consistent with the other line that uses "yet"

Change-Id: I6cae354b61ac673bb4d93a878daf01cebbf67a0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6459922
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Allen Li <ayatane@chromium.org>
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>

git_auth.py

@@ -603,7 +603,7 @@ class ConfigWizard(object):
                 'These may use different Gerrit hosts and need to be configured separately.'
             )
             self._println_action(
-                "If you haven't already, run `git cl creds-check --global` to configure common Gerrit hosts."
+                "If you haven't yet, run `git cl creds-check --global` to configure common Gerrit hosts."
             )
 
     # Configuring Git for Gerrit auth