Modify test_doesnt_fail_on_missing_detectors to not use file re #8227

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Remove indent of wiki description re #8227

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge branch 'feature/8227_no_file_read_load' into develop