[NXOS] learn("isis") crashes

[jlmcgraw]

This is due to two separate issues:

• The area address regex does not account for addresses with hex
• Schemas that don't allow for VRFs configurations that are valid but missing some information (e.g. interfaces)

Traceback (most recent call last):
  File "/network/user/genie_learn_isis/genie_learn_isis.py", line 59, in <module>
    main()
  File "/network/user/genie_learn_isis/genie_learn_isis.py", line 41, in main
    model_data = devices.learn("isis").to_dict()
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "src/genie/conf/base/device.py", line 640, in genie.conf.base.device.Device.learn
  File "/network/user/genie_learn_isis/venv/lib64/python3.11/site-packages/genie/libs/ops/isis/nxos/isis.py", line 397, in learn
    self.make()
  File "/network/user/genie_learn_isis/venv/lib64/python3.11/site-packages/genie/ops/base/base.py", line 111, in make
    self.maker.make(*args, **kwargs)
  File "src/genie/ops/base/maker.py", line 326, in genie.ops.base.maker.Maker.make
  File "src/genie/ops/base/maker.py", line 440, in genie.ops.base.maker.Maker._call_parser
  File "src/genie/metaparser/_metaparser.py", line 342, in genie.metaparser._metaparser.MetaParser.parse
  File "src/genie/metaparser/_metaparser.py", line 322, in genie.metaparser._metaparser.MetaParser.parse
  File "src/genie/metaparser/util/schemaengine.py", line 419, in genie.metaparser.util.schemaengine.Schema.validate
genie.metaparser.util.exceptions.SchemaMissingKeyError: Missing keys: [['instance', '65300', 'vrf', 'wsatm', 'area_address'], ['instance', '65300', 'vrf', 'wdeprod', 'area_address'], ['instance', '65300', 'vrf', 'controller', 'area_address'], ['instance', '65300', 'vrf', 'default', 'area_address'], ['instance', '65300', 'vrf', 'was-ne', 'area_address'], ['instance', '65300', 'vrf', 'iwn-orbit', 'area_address'], ['instance', '65300', 'vrf', 'nonprod', 'area_address'], ['instance', '65300', 'vrf', 'restriction', 'area_address'], ['instance', '65300', 'vrf', 'wan-netconf', 'area_address'], ['instance', '65300', 'vrf', 'sher', 'area_address']]

[jlmcgraw]

Candidate fix in #969