treat / as root for restore of onedrive and sharepoint (#3328)

<!-- PR description-->

passing '/' will select anything for backup details and restore for onedrive and sharepoint

#### 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

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #https://github.com/alcionai/corso/issues/3252
#### Test Plan

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

src/cli/utils/flags.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/alcionai/corso/src/internal/common/dttm"
 	"github.com/alcionai/corso/src/pkg/path"
+	"github.com/alcionai/corso/src/pkg/selectors"
 )
 
 // common flag vars (eg: FV)
@@ -215,6 +216,11 @@ func trimFolderSlash(folders []string) []string {
 	res := make([]string, 0, len(folders))
 
 	for _, p := range folders {
+		if p == string(path.PathSeparator) {
+			res = selectors.Any()
+			break
+		}
+
 		// Use path package because it has logic to handle escaping already.
 		res = append(res, path.TrimTrailingSlash(p))
 	}

src/cli/utils/onedrive_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/alcionai/corso/src/cli/utils"
 	"github.com/alcionai/corso/src/internal/tester"
+	"github.com/alcionai/corso/src/pkg/path"
 )
 
 type OneDriveUtilsSuite struct {
@@ -26,6 +27,7 @@ func (suite *OneDriveUtilsSuite) TestIncludeOneDriveRestoreDataSelectors() {
 		containsOnly      = []string{"contains"}
 		prefixOnly        = []string{"/prefix"}
 		containsAndPrefix = []string{"contains", "/prefix"}
+		onlySlash         = []string{string(path.PathSeparator)}
 	)
 
 	table := []struct {
@@ -87,6 +89,15 @@ func (suite *OneDriveUtilsSuite) TestIncludeOneDriveRestoreDataSelectors() {
 			},
 			expectIncludeLen: 2,
 		},
+		{
+			name: "folder with just /",
+			opts: utils.OneDriveOpts{
+				Users:      empty,
+				FileName:   empty,
+				FolderPath: onlySlash,
+			},
+			expectIncludeLen: 1,
+		},
 	}
 	for _, test := range table {
 		suite.Run(test.name, func() {

src/cli/utils/sharepoint_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/alcionai/corso/src/cli/utils"
 	"github.com/alcionai/corso/src/internal/common/dttm"
 	"github.com/alcionai/corso/src/internal/tester"
+	"github.com/alcionai/corso/src/pkg/path"
 	"github.com/alcionai/corso/src/pkg/selectors"
 )
 
@@ -30,6 +31,7 @@ func (suite *SharePointUtilsSuite) TestIncludeSharePointRestoreDataSelectors() {
 		containsOnly      = []string{"contains"}
 		prefixOnly        = []string{"/prefix"}
 		containsAndPrefix = []string{"contains", "/prefix"}
+		onlySlash         = []string{string(path.PathSeparator)}
 	)
 
 	table := []struct {
@@ -182,6 +184,13 @@ func (suite *SharePointUtilsSuite) TestIncludeSharePointRestoreDataSelectors() {
 			},
 			expectIncludeLen: 2,
 		},
+		{
+			name: "folder with just /",
+			opts: utils.SharePointOpts{
+				FolderPath: onlySlash,
+			},
+			expectIncludeLen: 1,
+		},
 	}
 	for _, test := range table {
 		suite.Run(test.name, func() {

src/cli/utils/testdata/opts.go

@@ -356,6 +356,13 @@ var (
 				FolderPath: selectors.Any(),
 			},
 		},
+		{
+			Name:     "FilesWithSingleSlash",
+			Expected: testdata.OneDriveItems,
+			Opts: utils.OneDriveOpts{
+				FolderPath: []string{"/"},
+			},
+		},
 		{
 			Name:     "FolderPrefixMatch",
 			Expected: testdata.OneDriveItems,
@@ -482,6 +489,13 @@ var (
 				FolderPath: selectors.Any(),
 			},
 		},
+		{
+			Name:     "LibraryItemsWithSingleSlash",
+			Expected: testdata.SharePointLibraryItems,
+			Opts: utils.SharePointOpts{
+				FolderPath: []string{"/"},
+			},
+		},
 		{
 			Name:     "FolderPrefixMatch",
 			Expected: testdata.SharePointLibraryItems,