Add unit tests for new nav

[ryankeairns]

Relates to #64018

Rough plan:

• ValidatedDualRange types ([EuiDualRange] + [EuiRangeInput] types are too permissive and don't match eui#3443)
• Improve CollapsibleNav tests (Fixes Recently Viewed links allowing them to close the nav when clicked #66280)
• Link object creation
• Truncation logic
• Header rendering

[elasticmachine]

Pinging @elastic/kibana-core-ui (Team:Core UI)

[kobelb]

The CollapsibleNav could also benefit from adding tests to ensure the clicks have their intended effect, and the interoperation with localStorage is behaving properly.

Outside of that, this is a super-nit and will go away in the near future, so I don't think it's absolutely necessary... The InternalChromeStart added a getNavType$ which currently doesn't have any coverage, but it's just passing through the UISettingsClient observable, so it's really a cosmetic.

[myasonik]

Opened elastic/eui#3443 to hopefully fix the type issue at the source instead of in Kibana