So while using ReSharper, I was trying to configure my Code Inspection settings and I ran into an issue with one particular case.
When trying to change the 'Suspicious type conversion or check' severity level from Warning to Error, I noticed the Error dropdown didn't exist for this case. After doing some looking around the internet I was unable to find any information as to why the 'Error' Severity would be missing from this case.
'Suspicious type conversion or check' is located under the 'Potential Code Quality Issues':