Export AlternativeMapping incorrectly assumed to be part of parameter value export when it wasn't the root mapping making it unusable without ParameterDefinitionMapping etc.
Re spine-tools/Spine-Toolbox#2339
Checklist before merging
[x] Documentation (also in Toolbox repo) is up-to-date
[x] Release notes in Toolbox repo have been updated
[x] Unit tests have been added/updated accordingly
Export
AlternativeMapping
incorrectly assumed to be part of parameter value export when it wasn't the root mapping making it unusable withoutParameterDefinitionMapping
etc.Re spine-tools/Spine-Toolbox#2339
Checklist before merging