[Library] Canceling "add to library" adds media anyway

*I'm submitting a ...*
- [x] bug report

## General information

### Prerequisites

* [x] Are you running the latest version? Yes: 0.13.21

### Description

There is no possibility to abort the process of adding media to the library, once the option "add to library" is selected.

### Steps to Reproduce

1. Use setting "always use original title for export" (default)
2. Open the context menu on media in the netflix addon and select "add to library"
3. You get a screen keyboard to enter the name of the media (movie or series) with the netflix name already inserted
4. If you press "cancel", the given name is taken and the media is added to the library, as if you would have selected "ok"

**Expected behavior:** [What you expected to happen]

The expected behaviour would be to cancel the process by clicking on the "cancel" button on the keyboard dialogue for the media name.

Update: I was unaware of the settings option "always use original title for export". Changed issue description to take this into account.

Reproduce the issue in the Netflix add-on for Kodi with “always use original title for export” enabled, then open the media name keyboard dialog and press Cancel. Trace the add-to-library flow from the “add to library” context-menu action; done means cancelling the dialog leaves the media out of the library while confirming still adds it.

Written by the indexing model from the issue text.