fix(components/theme): missing line height token in modern v2 (#3524)

[AB#3402805](https://dev.azure.com/blackbaud/Products/_boards/board/t/SKY%20UX%20Program/Stories?System.AssignedTo=%40me&workitem=3402805)

---------

Co-authored-by: Sandhya Adhirvuh <[email protected]>
Co-authored-by: John White <[email protected]>

Author: 3 people

apps/playground/src/app/components/action-bars/summary-action-bar/summary-action-bar-modal.component.html

@@ -1,6 +1,18 @@
 <sky-modal>
   <sky-modal-header> Summary Action Bar In Modal </sky-modal-header>
-  <sky-modal-content> Content A </sky-modal-content>
+  <sky-modal-content>
+    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam ac tempor
+    erat. Duis facilisis, massa vestibulum consequat semper, urna lacus
+    sollicitudin neque, eget pulvinar mauris nulla ac sem. Maecenas at aliquam
+    nisl. Suspendisse elementum mollis est, eu tincidunt dolor pulvinar ut.
+    Proin nec viverra eros. Nam consectetur lectus ut pulvinar mattis. Mauris
+    vitae porta mauris. Integer bibendum at lorem non blandit. Integer ac leo
+    elit. Nullam accumsan tortor vitae malesuada tristique. Integer non viverra
+    urna, sed mattis dui. Suspendisse aliquet enim scelerisque justo auctor
+    tempor. Sed at risus rutrum, efficitur sem eu, efficitur ex. Curabitur
+    commodo, elit et varius imperdiet, lorem risus dignissim lorem, euismod
+    pulvinar leo est sit amet eros.
+  </sky-modal-content>
   <sky-modal-footer>
     <sky-summary-action-bar [formErrors]="error">
       <sky-summary-action-bar-actions>

libs/components/theme/src/lib/styles/themes/modern/_theme.scss

@@ -12,11 +12,11 @@
   );
   --sky-override-form-font-weight: var(--sky-font-weight-body-m);
   --sky-override-p-line-height: var(--sky-font-line_height-body-m);
+  --sky-override-body-line-height: normal;
 }
 
 @include compatMixins.sky-modern-v2-html {
   font-size: initial;
-  line-height: calc(20 / 14);
 }
 
 .sky-theme-modern {
@@ -41,6 +41,13 @@
     color $sky-transition-time-short;
 }
 
+body.sky-theme-modern {
+  line-height: var(
+    --sky-override-body-line-height,
+    var(--sky-font-line_height-body-m)
+  );
+}
+
 .sky-theme-modern {
   a {
     color: var(--sky-color-text-action);
@@ -99,7 +106,10 @@
   }
 
   p {
-    line-height: var(--sky-override-p-line-height);
+    line-height: var(
+      --sky-override-p-line-height,
+      var(--sky-font-line_height-body-m)
+    );
   }
 
   mark.sky-highlight-mark {