fix type issue

Author: msanlli

control-station/src/components/GaugeTag/TextData/TextData.tsx

@@ -16,7 +16,7 @@ export const TextData = memo(
             <div className={styles.textData}>
                 <div className={styles.name}>{name}</div>
                 <div className={styles.value}>
-                    {lostConnection ? '-.--' : value.toFixed(2)}
+                    {lostConnection || value === null ? '-.--' : value.toFixed(2)}
                 </div>
                 <div className={styles.units}>{units}</div>
                 <div className={styles.min}>{min && `min: ${min}`}</div>