Use separate KoQ for coordinate length values

[hl662]

Following iTwin/itwinjs-core#8399, which is available in core 5.1.0:

• Fix documentation to clarify RRU.BEARING, not RRU.Bearing for bearing measurement.
• Use separate KoQ for coordinate values, AecUnits.LENGTH_COORDINATE to format values specific to coordinates, separate from standard length values.
• Update peerDeps for @itwin/measure-tool-react's itwin-core packages to 5.1.0 to support length coordinate koq.
• Update test viewer to use 5.1.0 itwin-core pkgs.
• Fallback to using QuantityTypes for measurements, in case older iModels doesn't include AecUnits. (Which can be a very common case after discovery in DesignReview with our older test iModels)

Tested: Observe the formatting of Distance in widget, the precision (4 places) is different from the precision (2 places) of the value in the start and end coordinates.