fix: Fixes javascript error for LLDP neighbor view

[abates]

The vanilla javascript rewrite of the LLDP neighbors view introduced a bug where an LLDP neighbor with a matching row (but no configured device) will raise an exception. This commit fixes that issue.

What's Changed

The recent LLDP view changes (in #5346) introduced a javascript bug. If the LLDP information returned includes a neighbor for a matching interface, but Nautobot has no configured device for that interface, then no DOM nodes match the query selectors for data attributes. Since no nodes match, no attributes can be looked up and an exception is thrown. This fix wraps all of the attribute lookups in a function that always returns a string (empty if not found).

Screenshots

No screenshots as the UI hasn't changed.

TODO

• Explanation of Change(s)
• Added change log fragment(s) (for more information see the documentation)
• Attached Screenshots, Payload Example
• Unit, Integration Tests
• Documentation Updates (when adding/changing features)
• Example App Updates (when adding/changing features)
• Outline Remaining Work, Constraints from Design