ospfd: mpls ldp-sync flag is not cleared if ldp-sync is disabled

[c-po]

Description

When enabling mpls ldp-sync under router ospf FRR ospfd configures SET_FLAG(ldp_sync_info->flags, LDP_SYNC_FLAG_IF_CONFIG); so internally knowing "hey - LDP was enabled", but the flag persists beeing enabled even if ldp-sync is turned off.

At first glance this might look like a cosmetic issue, but the internal state flags should be in sync with the actual CLI configuration, even that the comment in the source states this:

frr/ospfd/ospf_ldp_sync.c

Lines 900 to 904 in 5203914

	/* disable LDP-SYNC on an interface
	* stop holddown timer if running
	* restore ospf cost
	*/
	SET_FLAG(ldp_sync_info->flags, LDP_SYNC_FLAG_IF_CONFIG);

Version

* stable/9.1
* master

How to reproduce

Start MPLS ldp-sync

!
interface eth0.203
 ip ospf mpls ldp-sync
exit
!
router ospf
 ospf router-id 172.18.254.203
 log-adjacency-changes
 mpls ldp-sync
 mpls ldp-sync holddown 60
exit
!

Disable MPLS ldp-sync

!
interface eth0.203
 no ip ospf mpls ldp-sync
exit
!
router ospf
 no mpls ldp-sync
exit
!

Expected behavior

no ip ospf mpls ldp-sync is not show in the interface context

vtysh -c "show run"

!
interface eth0.203
exit
!
router ospf
 ospf router-id 172.18.254.203
 log-adjacency-changes
exit
!

Actual behavior

Interface keeps showing ldp-sync is disabled on vtysh, but the entire ldp-sync section is gone, this feels "wrong"

vtysh -c "show run"

!
interface eth0.203
 no ip ospf mpls ldp-sync
exit
!
router ospf
 ospf router-id 172.18.254.203
 log-adjacency-changes
exit
!

Additional context

No response

Checklist

• I have searched the open issues for this bug.
• I have not included sensitive information in this report.