adds error for list name exists

src/pkg/services/m365/api/graph/errors.go

@@ -131,6 +131,8 @@ var (
 	ErrResourceLocked = clues.New("resource has been locked and must be unlocked by an administrator")
 
 	ErrTokenExpired = clues.New("jwt token expired")
+
+	ErrNameAlreadyExistsConflict = clues.New("Name already exists")
 )
 
 func IsErrApplicationThrottled(err error) bool {

src/pkg/services/m365/api/lists_test.go

@@ -758,6 +758,7 @@ func (suite *ListsAPIIntgSuite) TestLists_PostList() {
 
 	_, err = acl.PostList(ctx, siteID, listName, oldListByteArray, fault.New(true))
 	require.Error(t, err)
+	assert.Equal(t, graph.ErrNameAlreadyExistsConflict, err)
 
 	newListItems := newList.GetItems()
 	require.Less(t, 0, len(newListItems))