[FIX] mail: fix link preview overflow in the chat window

Before this PR, a link preview image would overflow out of the chat window. This
because the max-width on the image is bigger than the space dedicated to the
image inside the chat window.
This PR set the max-width to 100% inside a chat window, so the image cover the
space nicely.

closes odoo/odoo#119019

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/static/src/core_ui/link_preview/link_preview.scss

@@ -17,7 +17,7 @@
 
 .o-mail-LinkPreviewImage img {
     max-height: $o-mail-LinkPreview-height;
-    max-width: $o-mail-LinkPreview-width;
+    max-width: Min($o-mail-LinkPreview-width, 100%);
 }
 
 .o-mail-LinkPreviewVideo {