[image_picker] Remove usesCleartextTraffic (#11076)

Removes deprecated usesCleartextTraffic. 

Addresses: #182553

## Pre-Review Checklist

Author: mboetger

packages/image_picker/image_picker/example/android/app/src/debug/AndroidManifest.xml

@@ -4,7 +4,7 @@
          to allow setting breakpoints, to provide hot reload, etc.
     -->
     <uses-permission android:name="android.permission.INTERNET"/>
-    <application android:usesCleartextTraffic="true">
+    <application>
         <activity
             android:name=".ImagePickerTestActivity"
             android:launchMode="singleTop"

packages/image_picker/image_picker/example/pubspec.yaml

@@ -23,7 +23,6 @@ dependencies:
 
 dev_dependencies:
   build_runner: ^2.1.10
-  espresso: ^0.4.0
   flutter_test:
     sdk: flutter
   integration_test: