Fix Touchables typescript errors (#4067)

## Description

After #4014 I've noticed some ts errors with old deprecated Touchables.
This PR fixes them.

## Test plan

`yarn ts-check`

Author: m-bert

packages/react-native-gesture-handler/src/components/touchables/GenericTouchable.tsx

@@ -31,9 +31,7 @@ interface InternalProps {
   onStateChange?: (oldState: TouchableState, newState: TouchableState) => void;
 }
 
-// TODO: maybe can be better
-// TODO: all clearTimeout have ! added, maybe they shouldn't ?
-type Timeout = ReturnType<typeof setTimeout> | null | undefined;
+type Timeout = ReturnType<typeof setTimeout> | undefined;
 
 /**
  * GenericTouchable is not intented to be used as it is.
@@ -70,7 +68,7 @@ export default class GenericTouchable extends Component<
     if (this.props.delayPressIn) {
       this.pressInTimeout = setTimeout(() => {
         this.moveToState(TOUCHABLE_STATE.BEGAN);
-        this.pressInTimeout = null;
+        this.pressInTimeout = undefined;
       }, this.props.delayPressIn);
     } else {
       this.moveToState(TOUCHABLE_STATE.BEGAN);
@@ -89,7 +87,7 @@ export default class GenericTouchable extends Component<
         this.pressOutTimeout ||
         setTimeout(() => {
           this.moveToState(TOUCHABLE_STATE.MOVED_OUTSIDE);
-          this.pressOutTimeout = null;
+          this.pressOutTimeout = undefined;
         }, this.props.delayPressOut);
     } else {
       this.moveToState(TOUCHABLE_STATE.MOVED_OUTSIDE);
@@ -105,7 +103,7 @@ export default class GenericTouchable extends Component<
           this.moveToState(TOUCHABLE_STATE.BEGAN);
         }
         this.moveToState(TOUCHABLE_STATE.UNDETERMINED);
-        this.pressOutTimeout = null;
+        this.pressOutTimeout = undefined;
       }, this.props.delayPressOut);
     } else {
       if (this.STATE === TOUCHABLE_STATE.UNDETERMINED) {
@@ -125,9 +123,9 @@ export default class GenericTouchable extends Component<
     clearTimeout(this.pressInTimeout);
     clearTimeout(this.pressOutTimeout);
     clearTimeout(this.longPressTimeout);
-    this.pressOutTimeout = null;
-    this.longPressTimeout = null;
-    this.pressInTimeout = null;
+    this.pressOutTimeout = undefined;
+    this.longPressTimeout = undefined;
+    this.pressInTimeout = undefined;
   }
 
   // All states' transitions are defined here.
@@ -189,7 +187,7 @@ export default class GenericTouchable extends Component<
       const shouldCallOnPress =
         !this.longPressDetected &&
         this.STATE !== TOUCHABLE_STATE.MOVED_OUTSIDE &&
-        this.pressOutTimeout === null;
+        this.pressOutTimeout === undefined;
       this.handleGoToUndetermined();
       if (shouldCallOnPress) {
         // Calls only inside component whether no long press was called previously
@@ -219,7 +217,7 @@ export default class GenericTouchable extends Component<
   onMoveOut() {
     // Long press should no longer be detected
     clearTimeout(this.longPressTimeout);
-    this.longPressTimeout = null;
+    this.longPressTimeout = undefined;
     if (this.STATE === TOUCHABLE_STATE.BEGAN) {
       this.handleMoveOutside();
     }