[Tree] left position should respect root in another table

[Bolid1]

This is pull reopen for pull #2146

If my category has a root in another table, the Nested Strategy should start the left position for each root separately.

Test case you can see in NestedTreeRootAssociationSubTest

Food <- stored in another table
| - Fruits should has [1, 4]
    | - Apples should has [2, 3]
Sports <- stored in another table
| - Summery should has [1, 6]
    | - Basketball should has [2, 3]
    | - Football should has [4, 5]

Current behaviour is

Food <- stored in another table
| - Fruits has [1, 4]
    | - Apples has [2, 3]
Sports <- stored in another table
| - Summery has [5, 10]
    | - Basketball has [6, 7]
    | - Football has [8, 9]

[phansys]

Related to #2001.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.