fix back navigation issues with flutter engine

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/addons/AddonInternalSettingsActivity.kt

@@ -57,6 +57,11 @@ class AddonInternalSettingsActivity : AppCompatActivity() {
         })
     }
 
+    override fun onSupportNavigateUp(): Boolean {
+        onBackPressedDispatcher.onBackPressed()
+        return true
+    }
+
     override fun onCreateView(parent: View?, name: String, context: Context, attrs: AttributeSet): View? =
         when (name) {
             EngineView::class.java.name -> components.core.engine.createView(context, attrs).asView()

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/addons/AddonsActivity.kt

@@ -28,4 +28,9 @@ class AddonsActivity : AppCompatActivity() {
             }
         }
     }
+
+    override fun onSupportNavigateUp(): Boolean {
+        onBackPressedDispatcher.onBackPressed()
+        return true
+    }
 }

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/addons/InstalledAddonDetailsActivity.kt

@@ -44,6 +44,11 @@ class InstalledAddonDetailsActivity : AppCompatActivity() {
         bindAddon(addon)
     }
 
+    override fun onSupportNavigateUp(): Boolean {
+        onBackPressedDispatcher.onBackPressed()
+        return true
+    }
+
     private fun bindAddon(addon: Addon) {
         scope.launch {
             try {

packages/flutter_mozilla_components/android/src/main/kotlin/eu/weblibre/flutter_mozilla_components/addons/WebExtensionActionPopupActivity.kt

@@ -54,6 +54,11 @@ class WebExtensionActionPopupActivity : AppCompatActivity() {
         })
     }
 
+    override fun onSupportNavigateUp(): Boolean {
+        onBackPressedDispatcher.onBackPressed()
+        return true
+    }
+
     override fun onCreateView(parent: View?, name: String, context: Context, attrs: AttributeSet): View? =
         when (name) {
             EngineView::class.java.name -> components.core.engine.createView(context, attrs).asView()