HIFI testing plot discrepancy

[jclarkeSTFC]

Found during manual testing for the 6.10 release, this is also present in 6.9.1.

Follow the HIFI Transverse Field Simultaneous Fitting section of the HIFI testing instructions. Near the end you will produce some tiled plots that look like this:

But in the testing instructions they look like this:

The top left image is quite different.

Platform/Version (please complete the following information):

• OS: Windows
• OS Version: 10
• Mantid Version 6.9.1 and 6.9.20240514.1920