Remove requirement for ".xpt" in test data sheet names

[ASL-rmarshall]

In the test data template, a ".xpt" suffix has been added to the name of each sheet representing a class. This was to allow the rule editor to import the test data. However, the maximum length of an Excel sheet name is 32 characters, so the class name for "StudyProtocolDocumentVersion" has to be truncated to allow space for the ".xpt" suffix. This causes the result dataset to be reported incorrectly as "STUDYPROTOCOLDOCUMENTVERSIO" (because it seems that the dataset name is derived from the filename instead of being retrieved from the Dataset metadata sheet).

This change requires updates to:

1. The rules editor.
2. The test data template.

[ASL-rmarshall]

The rules editor change is part of cdisc-org/conformance-rules-editor#218, so this PBI can be used for the test data template updates.

[ASL-rmarshall]

Technically, this is still needed but it is low priority