Make attachments open in a new tab/browser

[SiriusXT]

Related to #553.

1. The changes in abstract_text_type_widget.js allow images to open in a new tab when holding down the Ctrl key.

2. It’s unclear why configureWebContents was originally executed only in the main window within src/services/window.ts, which prevented configureWebContents from working properly in the extra window. Therefore, I removed:

if (!mainWindow) {
    return;
}

because it prevented extraWindow from opening links in the browser.