Remove rule squashing all paragraphs in pending batch comments

...and move it into a more specific rule.

ee/app/assets/stylesheets/components/batch_comments/draft_note.scss

@@ -4,10 +4,6 @@ $draft-actions-left-margin: 40px + $gl-padding;
   margin: 0;
   background: $orange-50;
 
-  p {
-    margin: 0;
-  }
-
   .drafts-count-component {
     @include transition(background-color);
     background: rgba($green-500, 0.2);
@@ -31,6 +27,8 @@ $draft-actions-left-margin: 40px + $gl-padding;
   }
 
   .draft-note-actions {
+    margin: 0;
+
     @include notes-media('min', map-get($grid-breakpoints, sm)) {
       margin-left: $draft-actions-left-margin;
     }

ee/changelogs/unreleased/defect-draft-comment-paragraph-space.yml

+---
+title: Pending (unsubmitted) review comments with multiple lines now display whitespace
+  before being submitted
+merge_request: 21435
+author:
+type: fixed