fix: correct a typo in config:set error messaging

[onlywade]

Fixes

When a user enters invalid arguments to the config:set command, the error message mistakenly references an incorrect command name, configs:set:

$ twilio config:set
 » No configuration is added to set. Run "twilio configs:set --help" to see how to set a configurations.

$ twilio configs:set --help
 ›   Error: command configs:set not found

$ twilio config:set --help

update Twilio CLI configurations.

USAGE
  $ twilio config:set
...

This change corrects that mistake in the error message (along with the corresponding test).

Checklist

• I acknowledge that all my contributions will be made under the project's license
• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the Contribution Guidelines and my PR follows them
• I have titled the PR appropriately
• I have updated my branch with the main branch
• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary documentation about the functionality in the appropriate .md file
• I have added inline documentation to the code I modified

[childish-sambino]

LGTM Thanks!