[FIX] website: fix email sharing subject format

Steps to reproduce:
- Drop a "Share" snippet anywhere on the page and save.
- Click on the email icon.
- Your default email client should open with, as a subject line, the
title of the page where spaces are replaced by +.
=> This should not be the case, spaces should show as spaces.

Since the sharer refactoring in [1], the title of a page used in share
buttons of the `s_share` snippet is encoded as a `URLSearchParams()`,
which encodes spaces as "+" characters (see the specs [2] of the
built-in method). This works fine for most share buttons, but not for
email clients, which do not properly parse the "+". Typically, that
means that the subject line of the mailto link is something like
"Home+%7C+My+Website", which renders as "Home+|+My+Website" in a mail
client, instead of showing spaces.

This commit uses another way to encode the title parameter, so that it
works for every share button. It also replaces a space that was encoded
twice for Whatsapp.

[1]: https://github.com/odoo/odoo/commit/5297388cd2aa1f693b04538c846c7025e243b09d
[2]: https://url.spec.whatwg.org/#ref-for-urlsearchparams%E2%91%A4

task-3603556

closes odoo/odoo#142876

Signed-off-by: Soukéina Bojabza (sobo) <sobo@odoo.com>

addons/website/static/src/snippets/s_share/000.js

@@ -59,9 +59,13 @@ const ShareWidget = publicWidget.Widget.extend({
                 // parameter, merging everything together, e.g of output:
                 // https://wa.me/?text=%20OpenWood%20Collection%20Online%20Reveal%20%7C%20My%20Website%20http%3A%2F%2Flocalhost%3A8888%2Fevent%2Fopenwood-collection-online-reveal-2021-06-21-2021-06-23-8%2Fregister
                 // For more details, see https://faq.whatsapp.com/general/chats/how-to-use-click-to-chat/
-                modifiedUrl.searchParams.set(titleParamFound, `${currentTitle}%20${currentUrl}`);
+                modifiedUrl.searchParams.set(titleParamFound, `${currentTitle} ${currentUrl}`);
             } else {
-                modifiedUrl.searchParams.set(titleParamFound, currentTitle);
+                // The built-in `URLSearchParams.set()` method encodes spaces
+                // as "+" characters, which are not properly parsed as spaces
+                // by email clients, so we can't use it here.
+                modifiedUrl.search = modifiedUrl.search
+                    .replace(encodeURIComponent("{title}"), encodeURIComponent(currentTitle));
             }
         }