Fix upload by sharing link with defensive check during mtime read

Since mtime is used to update cache and is not on critical path,
we can make it optional. If it's not available, cache behaviour
will suffer, but sharing should not fail.

Fixes #7587

Signed-off-by: Chris Narkiewicz <hello@ezaquarii.com>

src/main/java/com/owncloud/android/ui/asynctasks/CopyAndUploadContentUrisTask.java

@@ -152,9 +152,11 @@ public class CopyAndUploadContentUrisTask extends AsyncTask<Object, Void, Result
                                                                  null,
                                                                  null)) {
                     if (cursor != null && cursor.moveToFirst()) {
-                        lastModified = cursor.getLong(
-                            cursor.getColumnIndexOrThrow(
-                                DocumentsContract.Document.COLUMN_LAST_MODIFIED));
+                        // this check prevents a crash when last modification time is not available on certain phones
+                        int columnIndex = cursor.getColumnIndex(DocumentsContract.Document.COLUMN_LAST_MODIFIED);
+                        if (columnIndex >= 0) {
+                            lastModified = cursor.getLong(columnIndex);
+                        }
                     }
                 }
 
@@ -173,7 +175,7 @@ public class CopyAndUploadContentUrisTask extends AsyncTask<Object, Void, Result
                 while ((count = inputStream.read(buffer)) > 0) {
                     outputStream.write(buffer, 0, count);
                 }
- 
+
                 if (lastModified != 0) {
                     try {
                         if (!cacheFile.setLastModified(lastModified)) {