DOCSP-28157 fix typo in Create an Atlas Data Lake Pipeline page (#278)

Author: kanchana-mongodb

source/tutorial/add-dataset-pipeline.txt

@@ -171,8 +171,8 @@ Create a Pipeline from the |service| UI
          partitioning.
 
       The most frequently queried fields should be listed towards the 
-      top because they will have a larger impact on performance and c
-      ost than fields listed lower down the list. The order of fields 
+      top because they will have a larger impact on performance and 
+      cost than fields listed lower down the list. The order of fields 
       is important in the same way as it is for :manual:`Compound 
       Indexes </core/index-compound/>`. Data is optimized for queries 
       by the first field, followed by the second field, and so on.