[REF] contacts: set mail module as dependency of contacts

Contact application allows notably to see the activity summary view on
customers activities. It require mail to be installed. As there is no
real use of contacts application without mail let us set mail as a
dependency of contacts. It seems a better solution than having a bridge
module between contacts and mail.

This commit is linked to task ID 1882545 and PR #26797.

addons/contacts/__manifest__.py

@@ -10,7 +10,7 @@
 This module gives you a quick view of your contacts directory, accessible from your home page.
 You can track your vendors, customers and other contacts.
 """,
-    'depends': ['base'],
+    'depends': ['base', 'mail'],
     'data': [
         'views/contact_views.xml',
     ],