Problem with units when using QuickStatements on a Wikibase

@magnusmanske, I have a custom Wikibase and the following QuickStatement:

      CREATE
      
      LAST	P1	Q2
      LAST	Den	"chemical compound"
      LAST	P7	"CCCCCOC1=C2C3=C(C(=O)CC3)C(=O)OC2=C4[C@@H]5C=CO[C@@H]5OC4=C1"	S14	Q5
      LAST	P3	"C₂₁H₂₀O₆"	S14	Q5
      LAST	P2	368.3807U3	S14	Q5
      LAST	Len	"foo"
      LAST	P9	"InChI=1S/C21H20O6/c1-2-3-4-8-24-14-10-15-18(12-7-9-25-21(12)26-15)19-17(14)11-5-6-13(22)16(11)20(23)27-19/h7,9-10,12,21H,2-6,8H2,1H3/t12-,21+/m0/s1"	S14	Q5
      LAST	P10	"VQBNVFKQPPPAER-LAJNKCICSA-N"

It works well, except for the line with 368.3807U3. When I include that I get the error it does not know about http://compoundcloud.wikibase.cloud/entity/Q3 not existing. This makes sense, because it should be https://compoundcloud.wikibase.cloud/entity/Q3 instead. With the 's'.

I am guessing the problem is that wikidata.org actually uses http in the URLs. I cannot see where in the code the translation to U3 to http://compoundcloud.wikibase.cloud/entity/Q3.

But since it is working as expected for other part of the QS, I am hoping the fix should be simple.

Start by tracing how the quantity value 368.3807U3 is parsed and how its unit URL is constructed for a custom Wikibase. Reproduce the supplied QuickStatement against the linked Wikibase, then verify that the unit resolves to an HTTPS entity URL while the other statements continue to work.