Add missing file after styles refactor

[MAILPOET-2822]

assets/css/src/components-plugin/_listing-newsletters.scss

@@ -0,0 +1,88 @@
+#newsletters_container {
+  h2.nav-tab-wrapper {
+    margin-bottom: 1rem;
+  }
+}
+
+.mailpoet_stats_text {
+  font-size: 14px;
+  font-weight: 600;
+}
+
+.mailpoet_stat_excellent {
+  color: $badge-color-excellent;
+}
+
+.mailpoet_stat_good {
+  color: $badge-color-good;
+}
+
+.mailpoet_stat_bad {
+  color: $badge-color-bad;
+}
+
+.mailpoet_stat_hidden {
+  display: none;
+}
+
+.mailpoet_stat_link_small {
+  font-size: .75rem;
+  text-decoration: underline !important;
+}
+
+.mailpoet_badge {
+  border-radius: 3px;
+  color: white;
+  cursor: pointer;
+  font-size: .5625rem;
+  font-weight: 500;
+  letter-spacing: 1px;
+  margin-right: 4px;
+  padding: 4px 6px 3px;
+  text-transform: uppercase;
+  vertical-align: middle;
+}
+
+.mailpoet_badge_excellent,
+.mailpoet_badge_teal {
+  background: $badge-color-excellent;
+}
+
+.mailpoet_badge_good,
+.mailpoet_badge_yellow {
+  background: $badge-color-good;
+}
+
+.mailpoet_badge_bad,
+.mailpoet_badge_red {
+  background: $badge-color-bad;
+}
+
+.mailpoet_badge_green {
+  background: $badge-color-green;
+}
+
+.mailpoet_badge_video {
+  background: $badge-color-video-guide;
+  display: inline-block;
+  line-height: 20px;
+  padding: 3px 6px;
+  text-decoration: none;
+  vertical-align: top;
+
+  &:hover,
+  &:active,
+  &:focus {
+    background: $badge-color-green;
+    color: #fff;
+  }
+
+  .dashicons {
+    font-size: 14px;
+    line-height: 20px;
+  }
+}
+
+.mailpoet_badge_video_grey {
+  background: #c3c3c3;
+}