fix: Fix fullscreen issue with bottomsheet (#8503)

## **Description**
- BottomSheetDialog's current fullscreen behavior attaches the Dialog to
the top of the screen instead of letting the height be dictated by the
maxScreenHeight, which factors in the safe area inset. This PR removes
the absolute `top:0` position of isFullscreen behavior

## **Related issues**

Fixes: 

## **Manual testing steps**

1. Go to Metamask Portfolio
2. Connect an account
3.

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

https://github.com/MetaMask/metamask-mobile/assets/14355083/f8dcc940-ea6e-4532-b76d-9dabf03b42a9

<!-- [screenshots/recordings] -->

### **After**

https://github.com/MetaMask/metamask-mobile/assets/14355083/c366f833-7efc-4d2e-b480-8fe0b67fc778

<!-- [screenshots/recordings] -->

## **Pre-merge author checklist**

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- [x] I've clearly explained what problem this PR is solving and how it
is solved.
- [x] I've linked related issues
- [x] I've included manual testing steps
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- [ ] I’ve included tests if applicable
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if applicable
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Not required for external contributors.
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  - [ ] In case it's not yet "ready for review", I've set it to "draft".
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## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

app/component-library/components/BottomSheets/BottomSheet/foundation/BottomSheetDialog/BottomSheetDialog.styles.ts

@@ -22,18 +22,13 @@ const styleSheet = (params: {
   const { vars, theme } = params;
   const { colors, shadows } = theme;
   const { maxSheetHeight, screenBottomPadding, isFullscreen } = vars;
-  const positionObject = isFullscreen
-    ? { ...StyleSheet.absoluteFillObject }
-    : {
-        position: 'absolute',
-        bottom: 0,
-        left: 0,
-        right: 0,
-      };
 
   return StyleSheet.create({
     base: Object.assign({
-      ...positionObject,
+      position: 'absolute',
+      bottom: 0,
+      left: 0,
+      right: 0,
     } as ViewStyle) as ViewStyle,
     sheet: {
       backgroundColor: colors.background.default,