Refs #24408

Refs #24408

Rather than just generating a nonsense error message on failure, catch
and throw a `FileError` with a clear message of what went wrong.

Problem identified: sample log entries are not case sensitive. title, Title will not result in different SampleLog entries

Refs #24312

Refs #24312

I think it is more appropriate to ask for title (a SampleLog entry) and not Title (the parameter name in the file)

The fix:
Title was not recognized as existing header component and repeated.

Refs #24312

Refs #24312

Refs #24312

Different choices of types for data. Nexus format only requires NXnumber
for a larger number of its fields.

Test V20 file added. This is the 10th iteraton of the input file

Needed for instrument loading.
Also re-instated the findGroup() function in NexusGeometryParser as the refactored
version was disfunctional (segfaults)

In LoadEventNexus, after having checked if an instrument XML is found in the file, first check if the file contains geometry in
the binary nexus data before searching for the instrument name.
The file is checked using the LoadGeometry::isNexus() function and if it returns true, LoadInstrument is called with a
filename as argument rather than instrument name.