Apply "Move padding from body top to header bottom""

The rule is to apply padding between header and body when body
is rendered.
However in collapsed state, body is rendered but we don't want
the padding, hence only apply padding when comment is not
collapsed.
See Change 345223 for the initial attempt.

Google-bug-id: b/244676327
Release-Notes: skip
Screenshot: https://imgur.com/a/THnI75x
Change-Id: I438d7d77b837406c4517dc148d16820c1f4af898

polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts

diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index b884941..f5e8a1a 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -359,13 +359,14 @@
         :host([saving]) .date {
           opacity: 0.5;
         }
-        .body {
-          padding-top: var(--spacing-m);
-        }
         .header {
           align-items: center;
           cursor: pointer;
           display: flex;
+          padding-bottom: var(--spacing-m);
+        }
+        :host([collapsed]) .header {
+          padding-bottom: 0px;
         }
         .headerLeft > span {
           font-weight: var(--font-weight-bold);