Keep the expiry message on screen with its own slider gate

The expiry error was written into the shared error state as a plain-send one,
so entering swap-send retracted it while the expiry flag stayed set: a
disabled slider with nothing on screen saying why. The message belongs to the
REQUEST, so the plain-send clear now refuses it. A source wallet or asset
switch retires whatever error is showing, for the same reason it already
retires the toggle and the learned route capabilities.

Author: j0ntz

src/components/scenes/SendScene2.tsx

@@ -282,7 +282,16 @@ const SendComponent: React.FC<Props> = props => {
   )
   const [expireDate, setExpireDate] = useState<Date | undefined>(initExpireDate)
   /** Whether the payment request's own countdown has run out. */
-  const [addressExpired, setAddressExpired] = useState<boolean>(false)
+  const [addressExpired, setAddressExpiredState] = useState<boolean>(false)
+  /**
+   * Mirror of `addressExpired` for the error-owner helpers below, which are
+   * also called from async effects holding an older render's closure.
+   */
+  const addressExpiredRef = React.useRef<boolean>(false)
+  const setAddressExpired = (value: boolean): void => {
+    addressExpiredRef.current = value
+    setAddressExpiredState(value)
+  }
   const [error, setError] = useState<unknown | undefined>(undefined)
   const [edgeTransaction, setEdgeTransaction] =
     useState<EdgeTransaction | null>(null)
@@ -382,6 +391,10 @@ const SendComponent: React.FC<Props> = props => {
   /** The converse: retract a plain-send error without touching a swap one. */
   const clearPlainSendError = (): void => {
     if (swapErrorShown.current) return
+    // The expiry message belongs to the REQUEST, not to either send mode, and
+    // the slider stays disabled on it either way. Retracting it here left the
+    // user looking at a dead slider with nothing on screen explaining why.
+    if (addressExpiredRef.current) return
     setError(undefined)
   }
 
@@ -1342,6 +1355,12 @@ const SendComponent: React.FC<Props> = props => {
           setRateStarvedFallback(false)
           setStealth(false)
           setRouteCaps({})
+          // The message describes the pair and wallet the user just left, the
+          // same reason the toggle and the route caps go. Through the owners,
+          // so `swapErrorShown` does not survive the wallet it belonged to.
+          clearSwapError()
+          setAddressExpired(false)
+          clearPlainSendError()
           // The recipients go with them, EVERY one of them. Clearing the
           // destination CHAIN while leaving an address behind drops the scene
           // back into plain-send mode still displaying a foreign-chain