Dedupe collection items for OneDrive (#2118)

## Description

Under some circumstances items can be returned multiple times when iterating through the endpoint. This dedupes items within a single collection.

It does not address the following:
* item being removed from the collection during iteration
* item appearing multiple times in different collections

## Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No 

## Type of change

- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [x] 🧹 Tech Debt/Cleanup

## Issue(s)

* #1954 

## Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/internal/connector/onedrive/collection.go

@@ -49,7 +49,7 @@ type Collection struct {
 	// represents
 	folderPath path.Path
 	// M365 IDs of file items within this collection
-	driveItems []models.DriveItemable
+	driveItems map[string]models.DriveItemable
 	// M365 ID of the drive this collection was created from
 	driveID       string
 	source        driveSource
@@ -79,6 +79,7 @@ func NewCollection(
 ) *Collection {
 	c := &Collection{
 		folderPath:    folderPath,
+		driveItems:    map[string]models.DriveItemable{},
 		driveID:       driveID,
 		source:        source,
 		service:       service,
@@ -101,7 +102,7 @@ func NewCollection(
 // Adds an itemID to the collection
 // This will make it eligible to be populated
 func (oc *Collection) Add(item models.DriveItemable) {
-	oc.driveItems = append(oc.driveItems, item)
+	oc.driveItems[*item.GetId()] = item
 }
 
 // Items() returns the channel containing M365 Exchange objects

src/internal/connector/onedrive/collection_test.go

@@ -62,12 +62,14 @@ func (suite *CollectionUnitTestSuite) TestCollection() {
 
 	table := []struct {
 		name         string
+		numInstances int
 		source       driveSource
 		itemReader   itemReaderFunc
 		infoFrom     func(*testing.T, details.ItemInfo) (string, string)
 	}{
 		{
-			name:   "oneDrive",
+			name:         "oneDrive, no duplicates",
+			numInstances: 1,
 			source:       OneDriveSource,
 			itemReader: func(context.Context, models.DriveItemable) (details.ItemInfo, io.ReadCloser, error) {
 				return details.ItemInfo{OneDrive: &details.OneDriveInfo{ItemName: testItemName}},
@@ -80,7 +82,36 @@ func (suite *CollectionUnitTestSuite) TestCollection() {
 			},
 		},
 		{
-			name:   "sharePoint",
+			name:         "oneDrive, duplicates",
+			numInstances: 3,
+			source:       OneDriveSource,
+			itemReader: func(context.Context, models.DriveItemable) (details.ItemInfo, io.ReadCloser, error) {
+				return details.ItemInfo{OneDrive: &details.OneDriveInfo{ItemName: testItemName}},
+					io.NopCloser(bytes.NewReader(testItemData)),
+					nil
+			},
+			infoFrom: func(t *testing.T, dii details.ItemInfo) (string, string) {
+				require.NotNil(t, dii.OneDrive)
+				return dii.OneDrive.ItemName, dii.OneDrive.ParentPath
+			},
+		},
+		{
+			name:         "sharePoint, no duplicates",
+			numInstances: 1,
+			source:       SharePointSource,
+			itemReader: func(context.Context, models.DriveItemable) (details.ItemInfo, io.ReadCloser, error) {
+				return details.ItemInfo{SharePoint: &details.SharePointInfo{ItemName: testItemName}},
+					io.NopCloser(bytes.NewReader(testItemData)),
+					nil
+			},
+			infoFrom: func(t *testing.T, dii details.ItemInfo) (string, string) {
+				require.NotNil(t, dii.SharePoint)
+				return dii.SharePoint.ItemName, dii.SharePoint.ParentPath
+			},
+		},
+		{
+			name:         "sharePoint, duplicates",
+			numInstances: 3,
 			source:       SharePointSource,
 			itemReader: func(context.Context, models.DriveItemable) (details.ItemInfo, io.ReadCloser, error) {
 				return details.ItemInfo{SharePoint: &details.SharePointInfo{ItemName: testItemName}},
@@ -119,7 +150,11 @@ func (suite *CollectionUnitTestSuite) TestCollection() {
 			// Set a item reader, add an item and validate we get the item back
 			mockItem := models.NewDriveItem()
 			mockItem.SetId(&testItemID)
+
+			for i := 0; i < test.numInstances; i++ {
 				coll.Add(mockItem)
+			}
+
 			coll.itemReader = test.itemReader
 
 			// Read items from the collection