Fix missing background colors for positive votes in reply dialog

Before- https://screenshot.googleplex.com/ARmqFqg2zfqnipR
After- https://screenshot.googleplex.com/jp3McevG9wpTmu4

Bug: 15170
Change-Id: Ieab07ebe0aa98ec71d01b837e3bbcdbffab6cc0f
diff --git a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_html.ts b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_html.ts
index 0af2f36..e21584e 100644
--- a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_html.ts
@@ -56,7 +56,7 @@
     gr-tooltip-content.iron-selected > gr-button[vote='max'] {
       --button-background-color: var(--vote-color-approved);
     }
-    gr-tooltip-content.iron-selected > gr-buttonvote='positive'] {
+    gr-tooltip-content.iron-selected > gr-button[vote='positive'] {
       --button-background-color: var(--vote-color-recommended);
     }
     gr-tooltip-content.iron-selected > gr-button[vote='min'] {