fast_charger_brand can be NULL, causes fatal error

Fatal error detected:
`sql: Scan error on column index 18, name "fast_charger_brand": converting NULL to string is unsupported`

Causes ChargeDetail API endpoint to fail. Solution was to add default string value for `fast_charger_brand`

src/v1_TeslaMateAPICarsChargesDetails.go

@@ -223,7 +223,7 @@ func TeslaMateAPICarsChargesDetailsV1(c *gin.Context) {
 				battery_heater_no_power,
 				conn_charge_cable,
 				fast_charger_present,
-				fast_charger_brand,
+				COALESCE(fast_charger_brand, '') as fast_charger_brand
 				fast_charger_type,
 				outside_temp
 			FROM charges