fix: make RTM_GETLINK return interfaces sorted by index

[iTrooz]

See & Fix #12885

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[milantracy]

RTM_GETLINK (when used with the NLM_F_DUMP flag) does not guarantee that interfaces are returned in numerical order by index

[EtiennePerot]

Yes, but if that's what it does in Linux then gVisor should have the same effective behavior.
What order does Linux use?

[iTrooz]

RTM_GETLINK (when used with the NLM_F_DUMP flag) does not guarantee that interfaces are returned in numerical order by index

Agreed, but Linux (tested with 6.19.10-arch1-1) currently has this behavior, and I've personally never seen ip a interfaces change orders dynamically, except in gVisor. That's why I think this change is an improvement

What order does Linux use?

RTM_GETLINK seems to always return interfaces sorted by index