Update new email templates (#28416)

Co-authored-by: Matt Jankowski <matt@jankowski.online>

app/javascript/styles/fonts/inter.scss

@@ -0,0 +1,8 @@
+@font-face {
+  font-family: Inter;
+  src: url('../fonts/inter/inter-variable-font-slnt-wght.woff2')
+    format('woff2-variations');
+  font-weight: 100 900;
+  font-style: normal;
+  mso-generic-font-family: swiss; /* stylelint-disable-line property-no-unknown -- Proprietary property for Outlook on Windows. */
+}