Provide tooltip for 1559 Gas Price field (#11436)

app/_locales/en/messages.json

@@ -647,6 +647,9 @@
   "editGasMedium": {
     "message": "Medium"
   },
+  "editGasPriceTooltip": {
+    "message": "This network uses an older version of gas pricing which requires a “Gas price” field. Gas price is the maximum amount you are willing to pay per unit of gas."
+  },
   "editGasTitle": {
     "message": "Edit gas fee"
   },

ui/components/app/advanced-gas-controls/advanced-gas-controls.component.js

@@ -85,7 +85,7 @@ export default function AdvancedGasControls() {
             titleText={t('gasPrice')}
             titleUnit="(GWEI)"
             onChange={setGasPrice}
-            tooltipText=""
+            tooltipText={t('editGasPriceTooltip')}
             titleDetailText=""
             value={gasPrice}
           />