Remove opacity from Swipeable action panels (#4271)

## Description

Row position and `opacity` depend on different SharedValue, which may
lead to them animating out of sync. Since we already have `overflow:
hidden;` setting `opacity` is not required.

Fixes #3897 

## Test plan

Tested on the existing Swipeable examples.

Author: m-bert

packages/react-native-gesture-handler/src/components/ReanimatedSwipeable/ReanimatedSwipeable.tsx

@@ -392,7 +392,6 @@ const Swipeable = (props: SwipeableProps) => {
 
   const leftActionAnimation = useAnimatedStyle(() => {
     return {
-      opacity: showLeftProgress.value === 0 ? 0 : 1,
       // Both action containers use `absoluteFill` and overlap, so the
       // inactive one must not intercept touches meant for the visible
       // actions.
@@ -426,7 +425,6 @@ const Swipeable = (props: SwipeableProps) => {
 
   const rightActionAnimation = useAnimatedStyle(() => {
     return {
-      opacity: showRightProgress.value === 0 ? 0 : 1,
       // Both action containers use `absoluteFill` and overlap, so the
       // inactive one must not intercept touches meant for the visible
       // actions.