Hide empty cells in prop table

Remove awkward space when no default value is specified in the prop definition.

packages/react-common-docs/src/components/Props/Props.tsx

@@ -313,9 +313,14 @@ const Props: React.FC<Props> = ({ of: ofAttr }) => {
                 <BodyCell
                   data-column-name={propDefaultValue ? 'Default' : undefined}
                 >
-                  <Code>
-                    {getPropTypeHtml(propDefaultValue)}
-                  </Code>
+                  {
+                    propDefaultValue
+                    && (
+                      <Code>
+                        {getPropTypeHtml(propDefaultValue)}
+                      </Code>
+                    )
+                  }
                 </BodyCell>
                 <BodyCell>
                   {prop.description}