Add multilanguage support for Team name reserved validation message.

[luisprmat]

When we create a team and the team's name belongs to reserved list the validation doesn't pass and we see a message that had hardcoded English strings, making it impossible to translate for non-English users.

Solutions

1. Wraps the validation message with Laravel's __() helper so they can be translated via language files: $fail(__('This team name is reserved and cannot be used.')),
2. Since this translation is an argument of the Closure $fail within a ValidationRule class which returns an instance of the Illuminate\Translation\PotentiallyTranslatedString class we can chain the ->translate() method: $fail('This team name is reserved and cannot be used.')->translate().

I have chosen the first option for consistency with the other translation strings.

[WendellAdriel]

Thanks for your contribution @luisprmat! 💪