Unex When Using Save Other Window In ISIS SANS Interface

[cailafinn]

Describe the bug
An unhandled exception occurs when using the "Save Other" window in the ISIS SANS GUI.

Seems to be as a result of the additional metadata being added. Poor test coverage meant it got through unnoticed this long.

To Reproduce

1. Run anything through the ISIS SANS GUI (loqdemo)
2. Click Save Other and save one of the output workspaces
3. Crash.

Expected behavior

• File is saved correctly.
• Test coverage is added to detect when issues like this occur.
• Manual testing instructions are present to test this widget.

Platform/Version (please complete the following information):

• OS: All
• OS Version: N/A
• Mantid Version 6.9.1

Additional context
Traceback:

Traceback (most recent call last):
File "C:\MantidInstall\scripts\Interface\ui\sans_isis\SANSSaveOtherWindow.py", line 63, in on_save_clicked
subscriber.on_save_clicked()
File "C:\MantidInstall\scripts\SANS\sans\gui_logic\presenter\save_other_presenter.py", line 49, in on_save_clicked
save_workspace_to_file(name_to_save, file_formats, filename, additional_run_numbers)
TypeError: save_workspace_to_file() missing 1 required positional argument: 'additional_metadata'