🔥(mail) replace google font Roboto

Google fonts are not GDPR. We remove them and use
system fonts instead.

Author: AntoLC

src/mail/mjml/partial/header.mjml

@@ -9,9 +9,8 @@
         {{ title }}
     </mj-preview>
     <mj-attributes>
-        <mj-font name="Roboto" href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;700;900&display=swap" />
         <mj-all
-            font-family="Roboto, -apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif"
+            font-family="-apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Cantarell, 'Helvetica Neue', sans-serif"
             font-size="16px"
             line-height="normal"
             color="#3A3A3A"