Fix: Cancel command if no time is given as int

[Rushaway]

Description

Before you can use sm_ban
If you put text and not int as time the plugin take it as permant length

Motivation and Context

Few bans was made due to admins doesn't know how to use the command line correctly.

How Has This Been Tested?

sm_ban <text_instead_of_int>
return [Sourcebans++] Usage: sm_ban <#userid|name> <time|0> [reason]

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.