Fix commons-app#2212: Fix back button behaviour in explore views (commons-app#2650)

Author: cypherop

app/src/main/AndroidManifest.xml

@@ -101,7 +101,8 @@
         <activity
             android:name=".category.CategoryImagesActivity"
             android:label="@string/title_activity_featured_images"
-            android:parentActivityName=".contributions.MainActivity" />
+            android:parentActivityName=".contributions.MainActivity"
+            android:configChanges="orientation|screenSize|keyboard"/>
 
         <activity
             android:name=".category.CategoryDetailsActivity"
@@ -111,7 +112,8 @@
         <activity
             android:name=".explore.categories.ExploreActivity"
             android:label="@string/title_activity_explore"
-            android:parentActivityName=".contributions.MainActivity" />
+            android:parentActivityName=".contributions.MainActivity"
+            android:configChanges="orientation|screenSize|keyboard" />
 
         <activity
             android:name=".explore.SearchActivity"

app/src/main/java/fr/free/nrw/commons/category/CategoryImagesActivity.java

@@ -127,19 +127,6 @@ public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
         forceInitBackButton();
     }
 
-    /**
-     * This method is called on backPressed when mediaDetailFragment is opened in the activity.
-     */
-    @Override
-    protected void onResume() {
-        if (supportFragmentManager.getBackStackEntryCount()==1){
-            //FIXME: Temporary fix for screen rotation inside media details. If we don't call onBackPressed then fragment stack is increasing every time.
-            //FIXME: Similar issue like this https://github.com/commons-app/apps-android-commons/issues/894
-            onBackPressed();
-        }
-        super.onResume();
-    }
-
     /**
      * Consumers should be simply using this method to use this activity.
      * @param context A Context of the application package implementing this class.

app/src/main/java/fr/free/nrw/commons/explore/categories/ExploreActivity.java

@@ -177,20 +177,6 @@ public void unregisterDataSetObserver(DataSetObserver observer) {
 
     }
 
-    /**
-     * This method is called on Screen Rotation
-     */
-    @Override
-    protected void onResume() {
-        if (supportFragmentManager.getBackStackEntryCount() == 1) {
-            //FIXME: Temporary fix for screen rotation inside media details. If we don't call onBackPressed then fragment stack is increasing every time.
-            //FIXME: Similar issue like this https://github.com/commons-app/apps-android-commons/issues/894
-            //
-            onBackPressed();
-        }
-        super.onResume();
-    }
-
     /**
      * This method is called on backPressed of anyFragment in the activity.
      * If condition is called when mediaDetailFragment is opened.