[Web] Don't try to remove context menu listeners when not initialized (#3814)

## Description

Adds an early return inside `removeContextMenuListeners` so that it
doesn't throw when `detach` and `dropHandler` are called consecutively.
This is possible in v3 api, where the gesture lifecycle isn't tied to
the detector component.

## Test plan

Found when working on
#3813,
not sure how to reproduce it outside of it, but to reproduce it there
use this:
```
import * as React from 'react';
import { Button, StyleSheet, Text, View } from 'react-native';
import {
  GestureDetector,
  InterceptingGestureDetector,
  useTap,
} from 'react-native-gesture-handler';

export const COLORS = {
  NAVY: '#001A72',
  KINDA_RED: '#FFB2AD',
  YELLOW: '#FFF096',
  KINDA_GREEN: '#C4E7DB',
  KINDA_BLUE: '#A0D5EF',
};

function TextWithTap() {
  const tap = useTap({
    onStart: () => {
      'worklet';
      console.log('Tapped on text in its own component!');
    },
  });

  return (
    <GestureDetector gesture={tap}>
      <Text style={{ fontSize: 24, color: COLORS.KINDA_GREEN }}>
        This text is rendered in a separate component.
      </Text>
    </GestureDetector>
  );
}

function NativeDetectorExample() {
  const [entireVisible, setEntireVisible] = React.useState(true);
  const [firstVisible, setFirstVisible] = React.useState(true);
  const [secondVisible, setSecondVisible] = React.useState(true);
  const [thirdVisible, setThirdVisible] = React.useState(true);
  const [secondKey, setSecondKey] = React.useState(0);
  const [firstHasCallback, setFirstHasCallback] = React.useState(true);

  const tapAll = useTap({
    onStart: () => {
      'worklet';
      console.log('Tapped on text!');
    },
  });

  const tapFirstPart = useTap({
    onStart: firstHasCallback ? () => {
      'worklet';
      console.log('Tapped on first part!');
    }: () => {
      'worklet';
      console.log('First part tapped, but no callback set.');
    },
  });

  const tapSecondPart = useTap({
    onStart: () => {
      'worklet';
      console.log('Tapped on second part!');
    },
  });

  return (
    <View style={styles.subcontainer}>
      <Button title={(firstVisible ? 'Hide' : 'Show') + ' entire text'} onPress={() => setEntireVisible(v => !v)} />
      <Button title={(firstVisible ? 'Hide' : 'Show') + ' first part'} onPress={() => setFirstVisible(v => !v)} />
      <Button title={(secondVisible ? 'Hide' : 'Show') + ' second part'} onPress={() => setSecondVisible(v => !v)} />
      <Button title={(thirdVisible ? 'Hide' : 'Show') + ' third part'} onPress={() => setThirdVisible(v => !v)} />

      <Button title="Re-mount second part" onPress={() => setSecondKey(k => k + 1)} />
      <Button title={(firstHasCallback ? 'Disable' : 'Enable') + ' callback on first text'} onPress={() => setFirstHasCallback(v => !v)} />

      {entireVisible && <InterceptingGestureDetector gesture={tapAll}>
        <Text style={{ fontSize: 18, textAlign: 'center' }}>
          Some text example running with RNGH
          {firstVisible && <GestureDetector gesture={tapFirstPart}>
            <Text style={{ fontSize: 24, color: COLORS.NAVY }}>
              {' '}
              try tapping on this part
            </Text>
          </GestureDetector>}
          {secondVisible && <GestureDetector gesture={tapSecondPart}>
            <Text key={secondKey} style={{ fontSize: 28, color: COLORS.KINDA_BLUE }}>
              {' '}
              or on this part
            </Text>
          </GestureDetector>}
          {thirdVisible && <>
            {' '}
            <TextWithTap />
          </>}
          {' '}
          this part is not special :(
        </Text>
      </InterceptingGestureDetector>}
    </View>
  );
}

export default function NativeTextExample() {
  return (
    <View style={styles.container}>
      <NativeDetectorExample />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
  },
  subcontainer: {
    flex: 1,
    gap: 8,
    alignItems: 'center',
    justifyContent: 'center',
  },
  header: {
    fontSize: 18,
    textAlign: 'center',
    paddingHorizontal: 24,
  },
});
```

and press `Hide entire text`

Author: j-piasecki

packages/react-native-gesture-handler/src/web/tools/GestureHandlerWebDelegate.ts

@@ -139,6 +139,10 @@ export class GestureHandlerWebDelegate
   }
 
   private removeContextMenuListeners(): void {
+    if (!this.initialized) {
+      return;
+    }
+
     this.ensureView(this.view);
 
     if (this.shouldDisableContextMenu()) {