style: in-context discussions style updates (#426)

* style: change size of postactionbar in incontext discussions

* style: change postfilterbar text color and style

* style: change side bar icon sizes accoording to figma

* style: change margin for post aacording to figmaa

* style: change add a post style aaccording to figma

* refactor: remove unnecessary spaces

* refactor: use lineheight24 aand fontstyle class

---------

Co-authored-by: Mehak Nasir <67791278+mehaknasir@users.noreply.github.com>

src/components/PostPreviewPane.jsx

@@ -33,13 +33,12 @@ function PostPreviewPane({
         </div>
       )}
       <div className="d-flex justify-content-end">
-        {!showPreviewPane
-        && (
+        {!showPreviewPane && (
           <Button
             variant="link"
             size="sm"
             onClick={() => setShowPreviewPane(true)}
-            className={`text-primary-500 p-0 ${editExisting && 'mb-4.5'}`}
+            className={`text-primary-500 font-style p-0 ${editExisting && 'mb-4.5'}`}
             style={{ lineHeight: '26px' }}
           >
             {intl.formatMessage(messages.showPreviewButton)}