[Class Editor] Missing operation names for custom layouts

[vin0401]

Some of the endpoints for custom layouts are strangely generated on the frontend side.
Most likely that is the operation name for the schema that is not set.
Currently we got those results:

pimcoreStudioApiClassCustomLayoutGet
pimcoreStudioApiClassCustomLayoutUpdate
pimcoreStudioApiClassCustomLayoutCreate
pimcoreStudioApiClassCustomLayoutDelete
pimcoreStudioApiClassCustomLayoutExport

And since renaming after 1.0 could be tricky and would take time until we can apply that,
we should have a look.