Add TenGigE interface mapping to BASE_INTERFACES

[Kani999]

New Pull Request

Have you:

• Updated the README if necessary? (no README change needed)
• Updated any configuration settings?
• Written a unit test?

Change Notes

Closes #841

• Added "TenGigE": "TenGigabitEthernet" to BASE_INTERFACES in netutils/constants.py, grouped with the other TenGig variants.
• Added unit test cases for canonical_interface_name (TenGigE0/0/0/1 → TenGigabitEthernet0/0/0/1) and abbreviated_interface_name (TenGigE0/0/0/1 → Te0/0/0/1) in tests/unit/test_interface.py.
• Added changelog fragment changes/841.added.

No REVERSE_MAPPING change is needed: abbreviated_interface_name canonicalizes via BASE_INTERFACES first, then uses the existing "TenGigabitEthernet": "Te" entry.

Justification

TenGigE is the literal interface name used by Cisco IOS-XR (e.g. TenGigE0/0/0/1), and it is the only Ethernet speed whose ...GigE variant is missing from BASE_INTERFACES — FortyGigE, FiftyGigE, HundredGigE, TwoHundredGigE, and FourHundredGigE are all present. Today canonical_interface_name("TenGigE0/0/0/1") returns the input unchanged, forcing consumers to maintain an addl_name_map workaround.