Exception class namespaces missing

[DorsetDigital]

In the themedCSS() and themedJavascript() methods, when a file is not present, an InvalidArgumentException is thrown.
There's a missing 'use' statement in the custom backend class, which means that when this happens, a not found error is thrown instead of the expected method:

'[Emergency] Uncaught Error: Class 'DorsetDigital\EnhancedRequirements\View\InvalidArgumentException' not found'

Adding use InvalidArgumentException; should sort it