Chat command leading space in messageContent [BUG]

[collectioncard]

Describe the bug
The messageContent parameter of the ChatCommandtemplate's executeChatCommand field will leave in the leading space of the string that is left from removing the bot's invocation phrase. For example, a command structured like this "!bot do thing" will have a message content of " do thing".

To Reproduce
Steps to reproduce the behavior:

1. Create a message content command
2. Use the command
3. Look at the messageContent field
4. See error

Expected behavior
The leading space should be removed