Removes reference to non-existent concept template "Alignment Geometry - Reusing Horizontal Layout" from IfcAlignment

[RickBrice]

The Concept usage section of IfcAlignment, for Alignment Layouts, references "Alignment Geometry - Reusing Horizontal Layout". This concept template does not exist. This PR deletes the reference.

[github-actions]

PR Validation -- schema generators

Checks:

• ✗ EXPRESS schema valid
• ✓ New entities present in structure.json
• ✓ MD docs for new entities
• ✓ PEnum convention
• ✓ New UML Psets/Qtos emitted
• ✓ Modified psets emitted
• ✗ Schema SHACL validation

Detected:

• New entities: (none)
• New PEnums: (none)
• New UML Psets/Qtos: (none)
• UML files changed: (none)
• MD docs changed: (none)

_{See workflow run for failure details.}

[RickBrice]

The ideal solution is to create an "Alignment Geometry - Reusing Horizontal Layout" concept template because there is ambiguity surrounding how to assign representations to the IfcAlignment, IfcAlignmentHorizontal, IfcAlignmentVertical and IfcAlignmentCant layouts with the reusing horizontal layout paradigm. Some of the open questions are:

• Representation ownership. Should all representations be contained within the parent IfcAlignment.Representation.Representations, within each child alignment's Representation.Representations, or split between them?
• Horizontal curve ownership. Should the IfcCompositeCurve representation of the horizontal layout be a representation on the parent IfcAlignment or on the IfcAlignmentHorizontal?
• All-or-nothing geometry. Is the presence of a geometric representation for one alignment a requirement for all alignments in the group to have geometric representations?
• Mixed representation types. Are mixed representation types valid within the same group — for example, one child alignment represented as an IfcGradientCurve and another as an IfcOffsetCurveByDistances?

However, adding a concept template would be considered a change of the schema so it can't be done with IFC 4x3. Therefore, the only reasonable way to correct the issue is to delete the reference to the non-existent CT.