GC: OneDrive/SharePoint WebURL Fix (#2596)

## Description
Changes: 
- Use of `ptr` package to ensure safe dereferencing of pointers
- Update to query to ensure that `sharepointIds` are part of the response
- Alternate method created to obtain originating sharepoint site url 
<!-- Insert PR description-->

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

- [x] ⛔ No 

## Type of change

<!--- Please check the type of change your PR introduces: --->
- [x] 🌻 Feature
- [x] 🐛 Bugfix


## Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* closes #1747<issue>

## Test Plan

<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual

src/internal/connector/onedrive/drive.go

@@ -179,6 +179,7 @@ func defaultItemPager(
 			"package",
 			"parentReference",
 			"root",
+			"sharepointIds",
 			"size",
 			"deleted",
 		},

src/internal/connector/onedrive/item.go

@@ -14,6 +14,7 @@ import (
 	"github.com/microsoftgraph/msgraph-sdk-go/models"
 	"github.com/pkg/errors"
 
+	"github.com/alcionai/corso/src/internal/common/ptr"
 	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/internal/connector/uploadsession"
@@ -194,9 +195,9 @@ func oneDriveItemInfo(di models.DriveItemable, itemSize int64) *details.OneDrive
 
 	return &details.OneDriveInfo{
 		ItemType:  details.OneDriveItem,
-		ItemName:  *di.GetName(),
-		Created:   *di.GetCreatedDateTime(),
-		Modified:  *di.GetLastModifiedDateTime(),
+		ItemName:  ptr.Val(di.GetName()),
+		Created:   ptr.Val(di.GetCreatedDateTime()),
+		Modified:  ptr.Val(di.GetLastModifiedDateTime()),
 		DriveName: parent,
 		Size:      itemSize,
 		Owner:     email,
@@ -280,36 +281,32 @@ func sharePointItemInfo(di models.DriveItemable, itemSize int64) *details.ShareP
 	// TODO: we rely on this info for details/restore lookups,
 	// so if it's nil we have an issue, and will need an alternative
 	// way to source the data.
+
 	gsi := di.GetSharepointIds()
 	if gsi != nil {
-		if gsi.GetSiteId() != nil {
-			id = *gsi.GetSiteId()
-		}
+		id = ptr.Val(gsi.GetSiteId())
+		url = ptr.Val(gsi.GetSiteUrl())
 
-		if gsi.GetSiteUrl() != nil {
-			url = *gsi.GetSiteUrl()
+		if len(url) == 0 {
+			url = constructWebURL(di.GetAdditionalData())
 		}
 	}
 
 	if reference != nil {
-		parent = *reference.GetDriveId()
+		parent = ptr.Val(reference.GetDriveId())
+		temp := ptr.Val(reference.GetName())
+		temp = strings.TrimSpace(temp)
 
-		if reference.GetName() != nil {
-			// EndPoint is not always populated from external apps
-			temp := *reference.GetName()
-			temp = strings.TrimSpace(temp)
-
-			if temp != "" {
-				parent = temp
-			}
+		if temp != "" {
+			parent = temp
 		}
 	}
 
 	return &details.SharePointInfo{
 		ItemType:  details.OneDriveItem,
-		ItemName:  *di.GetName(),
-		Created:   *di.GetCreatedDateTime(),
-		Modified:  *di.GetLastModifiedDateTime(),
+		ItemName:  ptr.Val(di.GetName()),
+		Created:   ptr.Val(di.GetCreatedDateTime()),
+		Modified:  ptr.Val(di.GetLastModifiedDateTime()),
 		DriveName: parent,
 		Size:      itemSize,
 		Owner:     id,
@@ -344,3 +341,36 @@ func driveItemWriter(
 
 	return uploadsession.NewWriter(itemID, url, itemSize), nil
 }
+
+// constructWebURL helper function for recreating the webURL
+// for the originating SharePoint site. Uses additional data map
+// from a models.DriveItemable that possesses a downloadURL within the map.
+// Returns "" if map nil or key is not present.
+func constructWebURL(adtl map[string]any) string {
+	var (
+		desiredKey = "@microsoft.graph.downloadUrl"
+		sep        = `/_layouts`
+		url        string
+	)
+
+	if adtl == nil {
+		return url
+	}
+
+	r := adtl[desiredKey]
+	point, ok := r.(*string)
+
+	if !ok {
+		return url
+	}
+
+	value := ptr.Val(point)
+	if len(value) == 0 {
+		return url
+	}
+
+	temp := strings.Split(value, sep)
+	url = temp[0]
+
+	return url
+}