Fixed blatant typo in regex

However, still failing test, even though ```PYTHONPATH=. fail2ban-regex -v fail2ban/tests/files/logs/screensharingd  /etc/fail2ban/filter.d/screensharingd.conf``` gives desired result

config/filter.d/screensharingd.conf

@@ -24,7 +24,7 @@ _daemon = screensharingd
 #          (?:::f{4,6}:)?(?P<host>[\w\-.^_]+)
 # Values:  TEXT
 #
-failregex = ^%(__prefix_line)sAuthentication: Authentication: FAILED :: User Name: .+ :: Viewer Address: <HOST> :: Type: DH$
+failregex = ^%(__prefix_line)sAuthentication: FAILED :: User Name: .+ :: Viewer Address: <HOST> :: Type: DH$
 
 # Option:  ignoreregex
 # Notes.:  regex to ignore. If this regex matches, the line is ignored.