SpecificHeatCapacityWater output unit check

#### Broken rules:
This method output unit is kJ/kgK, which is not SI.

I have given this compliance check its own issue, as it will require a bit of work to see if there are any knock-on effects of adjusting the output for SI/BHoM compliance.

#### Suggestions to restore compliance:
Check for any knock-on effects of fixing this method. If acceptable to fix, then multiply output by 1000 and update output attribute.

Start at the SpecificHeatCapacityWater method and inspect its output attribute and all usages to identify possible knock-on effects. Confirm whether changing the output to SI units is acceptable, then update the value and attribute only if affected consumers remain correct; verify the relevant existing checks or tests if available.

Written by the indexing model from the issue text.