fix: Set Root as Parent if no parent in new tree view node

[marination]

Issue:

• No parent even after save if no parent is set
  

Fix:

• While creating a new Customer Group/ Territory / Sales Person from List View, if no Parent is filled, fetch root node as parent, just like Supplier Group

[marination]

@Mergifyio backport version-13-beta-pre-release

[mergify]

Command backport version-13-beta-pre-release: pending

Waiting for the pull request to get merged

[marination]

@Mergifyio backport version-12-hotfix

[mergify]

Command backport version-12-hotfix: pending

Waiting for the pull request to get merged

[mergify]

Command backport version-12-hotfix: failure

No backport have been created

• Backport to branch version-12-hotfix failed

Cherry-pick of 3e93a2f has failed:

On branch mergify/bp/version-12-hotfix/pr-22497
Your branch is up to date with 'origin/version-12-hotfix'.

You are currently cherry-picking commit 3e93a2f67f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:

	modified:   erpnext/setup/doctype/customer_group/customer_group.py
	modified:   erpnext/setup/doctype/sales_person/sales_person.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)

	both modified:   erpnext/setup/doctype/territory/territory.py

[mergify]

Command backport version-13-beta-pre-release: failure

No backport have been created

• Backport to branch version-13-beta-pre-release failed