The refrigerator cabinet temperature was always 10+ higher than the temperature I had selected using the Fridge button. Worse, the temperature would rise to 55F when the setpoint was 34F. However, the freezer cabinet worked fine, which seemed to indicate the compressor and other systems were fine. On a hunch and based on the diagnostic code, I purchased the replacement temperature sensor and installed it per the video posted by AppliancePartsPros.com It was a simple job - the worst part being emptying the fridge of food.
A thing to note about this particular refrigerator (GFSL6KEXALS) is that upon power up it displays an error code at the top of the cabinet that indicates a component failure. In my case, it displayed an 86. The 6 in this case is indicated as a Refrigerator Sensor Error Code - thus helping me home in on the sensor as being faulty. I also purchased the Technical Service Guide for this refrigerator, which explains all the error codes. You can likely find the manual online as I did (for a fee).
Another thing to note is that my problems with this refrigerator began with water pooling and freezing underneath the deli drawer. Apparently, the previous owners didn't think this was a problem. I cleared the obstruction in the drain inlet under the evaporator unit. But that likely then enabled me to focus on the temperature issue. Both problems likely were occurring at the same time.
Kudos to Appliance Parts Pros!