GC: Remove DeadCode (#1253)

## Description
Code removal from GraphConnector
`AddItemsToCollection` removed from graph_connector.go
## Type of change

- [x] 🐹 Trivial/Minor

## Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

## Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/internal/connector/exchange/service_functions.go

@@ -4,14 +4,11 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/hashicorp/go-multierror"
 	msgraphsdk "github.com/microsoftgraph/msgraph-sdk-go"
-	msgraphgocore "github.com/microsoftgraph/msgraph-sdk-go-core"
 	"github.com/microsoftgraph/msgraph-sdk-go/models"
 	"github.com/pkg/errors"
 
 	"github.com/alcionai/corso/src/internal/connector/graph"
-	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/pkg/account"
 	"github.com/alcionai/corso/src/pkg/path"
 	"github.com/alcionai/corso/src/pkg/selectors"
@@ -332,77 +329,3 @@ func pathAndMatch(qp graph.QueryParams, category path.CategoryType, c graph.Cach
 		return nil, false
 	}
 }
-
-func AddItemsToCollection(
-	ctx context.Context,
-	gs graph.Service,
-	userID string,
-	folderID string,
-	collection *Collection,
-) error {
-	// TODO(ashmrtn): This can be removed when:
-	//   1. other data types have caching support
-	//   2. we have a good way to switch between the query for items for each data
-	//      type.
-	//   3. the below is updated to handle different data categories
-	//
-	// The alternative would be to eventually just have collections fetch items as
-	// they are read. This would allow for streaming all items instead of pulling
-	// the IDs and then later fetching all the item data.
-	if collection.FullPath().Category() != path.EmailCategory {
-		return errors.Errorf(
-			"unsupported data type %s",
-			collection.FullPath().Category().String(),
-		)
-	}
-
-	options, err := optionsForFolderMessages([]string{"id"})
-	if err != nil {
-		return errors.Wrap(err, "getting query options")
-	}
-
-	messageResp, err := gs.Client().UsersById(userID).MailFoldersById(folderID).Messages().Get(ctx, options)
-	if err != nil {
-		return errors.Wrap(
-			errors.Wrap(err, support.ConnectorStackErrorTrace(err)),
-			"initial folder query",
-		)
-	}
-
-	pageIter, err := msgraphgocore.NewPageIterator(
-		messageResp,
-		gs.Adapter(),
-		models.CreateMessageCollectionResponseFromDiscriminatorValue,
-	)
-	if err != nil {
-		return errors.Wrap(err, "creating graph iterator")
-	}
-
-	var errs *multierror.Error
-
-	err = pageIter.Iterate(ctx, func(got any) bool {
-		item, ok := got.(graph.Idable)
-		if !ok {
-			errs = multierror.Append(errs, errors.New("item without ID function"))
-			return true
-		}
-
-		if item.GetId() == nil {
-			errs = multierror.Append(errs, errors.New("item with nil ID"))
-			return true
-		}
-
-		collection.AddJob(*item.GetId())
-
-		return true
-	})
-
-	if err != nil {
-		errs = multierror.Append(errs, errors.Wrap(
-			errors.Wrap(err, support.ConnectorStackErrorTrace(err)),
-			"getting folder messages",
-		))
-	}
-
-	return errs.ErrorOrNil()
-}