[IndexTable] Shift click (multiselect) is broken

[kyledurand]

Our checkboxes are custom where the label does the actual work when click happens. Firefox doesn't allow the click event to bubble up on the label when shift is held down

https://bugzilla.mozilla.org/show_bug.cgi?id=559506#:~:text=18%20days%20ago-,If%20you%20shift%2Bclick%20or%20ctrl%2Bclick%20on%20a%20label,checkbox%2C%20checkbox%20is%20not%20checked.