test: update CLI references to remove cost set variables command

- Remove 'indexer cost set variables' from indexer-cost.stdout
- Remove 'indexer cost set variables' from indexer-help.stdout

Part of refactor: remove multi-network support

Author: dwerner

packages/indexer-cli/src/__tests__/references/indexer-cost.stdout

@@ -1,7 +1,6 @@
 Manage costing for subgraphs
 
-  indexer cost set variables    Update cost model variables              
-  indexer cost set model        Update a cost model                      
-  indexer cost get              Get cost models for one or all subgraphs 
-  indexer cost delete           Remove one or many cost models           
-  indexer cost                  Manage costing for subgraphs             
+  indexer cost set model    Update a cost model                      
+  indexer cost get          Get cost models for one or all subgraphs 
+  indexer cost delete       Remove one or many cost models           
+  indexer cost              Manage costing for subgraphs             

packages/indexer-cli/src/__tests__/references/indexer-help.stdout

@@ -18,7 +18,6 @@ Manage indexer configuration
   indexer provision                  Manage indexer's provision                                       
   indexer disputes get               Cross-check POIs submitted in the network                        
   indexer disputes                   Configure allocation POI monitoring                              
-  indexer cost set variables         Update cost model variables                                      
   indexer cost set model             Update a cost model                                              
   indexer cost get                   Get cost models for one or all subgraphs                         
   indexer cost delete                Remove one or many cost models