feat(email): add new email graphic, switch to SVG (#5124) r=ryanfeeley

* feat(email): add new email graphic, switch to SVG

Fixes #5105

app/scripts/templates/confirm.mustache

@@ -12,7 +12,7 @@
     <div class="error"></div>
     <div class="success"></div>
 
-    <div class="graphic graphic-mail">{{#t}}Email Sent{{/t}}</div>
+    <div class="graphic graphic-mail"></div>
 
     {{#isSignUp}}
     <p class="verification-email-message">{{#unsafeTranslate}}Check your email for the verification link sent&nbsp;to %(escapedEmail)s{{/unsafeTranslate}}</p>

app/scripts/templates/confirm_reset_password.mustache

@@ -7,7 +7,7 @@
     <div class="error"></div>
     <div class="success"></div>
 
-    <div class="graphic graphic-mail">{{#t}}Email Sent{{/t}}</div>
+    <div class="graphic graphic-mail"></div>
 
     <p class="verification-email-message">{{#t}}Click on the link we've emailed you at %(email)s within the next hour to create a new password.{{/t}}</p>
 

app/styles/modules/_graphic.scss

@@ -26,12 +26,17 @@
 }
 
 .graphic-mail {
-  @include hidpi-background-image('graphic_mail', 150px 130px);
-  margin-bottom: 25px;
-  padding-bottom: 10px;
+  background-image: url('/images/graphic_mail.svg');
+  background-position: center center;
+  height: 130px;
+  width: auto;
 
   @include respond-to('small') {
-    background-size: 120px 104px;
+    height: 100px;
+  }
+
+  @include respond-to('trustedUI') {
+    margin: 0 auto 0 auto;
   }
 }