[FIX] web_editor: allow copy-pasting link target

The `target` attribute for a link specifies where that link should open
(for example, in a new tab). Previously, copy-pasting links in the
website editor (within text blocks for example) would remove the
`target` attribute. This implied loss of functionality.

This commit whitelists the `target` attribute to fix that behavior.

task-3184150

closes odoo/odoo#113908

X-original-commit: 1464752aca36198e5fed5dc8f5b5041244e6e4a9
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js

@@ -166,7 +166,7 @@ export const CLIPBOARD_WHITELISTS = {
         /^btn/,
         /^fa/,
     ],
-    attributes: ['class', 'href', 'src'],
+    attributes: ['class', 'href', 'src', 'target'],
     styledTags: ['SPAN', 'B', 'STRONG', 'I', 'S', 'U', 'FONT'],
     styles: {
         'text-decoration': { defaultValues: ['', 'none'] },