Issue with square brackets [] in attachment name

[sosnovsky]

customer report:

For extension 8.4.8 and above : When an attachment name contains [] it deletes a part of the name. (ex : [test]example_name.docx)

[sosnovsky]

Happens with long filenames, for example [Green] Something-deployement_installation.docx.txt

[sosnovsky]

fixed in #5382