Handle "message" variable being undefined/null

[acollierr17]

https://github.com/suggestionsbot/suggestions-bot/blob/9917b6750166ef665009da335a5f84e2d15621af/src/commands/Suggestions/suggest.js#L114

This is somewhat of regression of #64. What I should do in this case is in the try block, I should have a conditional checking for if message still exists before doing any actions on it. Otherwise, I should ignore it altogether. This would also be accounted for in the catch block.