[Users] mimeview_open_part_with -- How do I disable the "Open with" confirmation dialog?

[Pierre Fortin]

The CV19 quarantine gives me some extra time to address back-burner
issues... :)

I'm fed up with the html plugins (litehtml, dillo & fancy) and decided to
simply use "O" (View->Message Part->Open with...") to use firefox.

However, it triggers an "Open with" confirmation dialog.  A quick look at
mimeview.c shows variables "automatic" and "remember"[1]; but I'm not
familiar enough with CM internals to see if there's a way to prevent this
dialog from popping up every time...  Clue?

[1] I may be incorrectly assuming these variables were intended to
disable this dialog... (?)

Thanks,
Pierre