Use custom cancel string everywhere

to fix missing somali translation for android.R.string.cancel

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -864,7 +864,7 @@ public class DownloadDialog extends DialogFragment
         final AlertDialog.Builder askDialog = new AlertDialog.Builder(context)
                 .setTitle(R.string.download_dialog_title)
                 .setMessage(msgBody)
-                .setNegativeButton(android.R.string.cancel, null);
+                .setNegativeButton(R.string.cancel, null);
         final StoredFileHelper finalStorage = storage;
 
 

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.java

@@ -2080,7 +2080,7 @@ public final class VideoDetailFragment
     private void showClearingQueueConfirmation(final Runnable onAllow) {
         new AlertDialog.Builder(activity)
                 .setTitle(R.string.clear_queue_confirmation_description)
-                .setNegativeButton(android.R.string.cancel, null)
+                .setNegativeButton(R.string.cancel, null)
                 .setPositiveButton(android.R.string.yes, (dialog, which) -> {
                     onAllow.run();
                     dialog.dismiss();
@@ -2096,7 +2096,7 @@ public final class VideoDetailFragment
             resolutions[i] = sortedVideoStreams.get(i).getResolution();
         }
         final AlertDialog.Builder builder = new AlertDialog.Builder(activity)
-                .setNegativeButton(android.R.string.cancel, null)
+                .setNegativeButton(R.string.cancel, null)
                 .setNeutralButton(R.string.open_in_browser, (dialog, i) ->
                         ShareUtils.openUrlInBrowser(requireActivity(), url)
                 );

app/src/main/res/layout/dialog_feed_group_create.xml

@@ -205,7 +205,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_toStartOf="@+id/confirm_button"
-            android:text="@android:string/cancel" />
+            android:text="@string/cancel" />
 
         <Button
             android:id="@+id/confirm_button"