Bug 1576798 - Changed css box length of Watch Expression pane r=davidwalsh

Differential Revision: https://phabricator.services.mozilla.com/D44863

--HG--
extra : moz-landing-system : lando

devtools/client/debugger/src/components/SecondaryPanes/Expressions.css

@@ -126,7 +126,7 @@
 }
 
 .expressions-list .tree.object-inspector .node.object-node {
-  max-width: calc(113% - var(--breakpoint-expression-right-clear-space));
+  max-width: calc(100% - 20px);
   min-width: 0;
   text-overflow: ellipsis;
   overflow: hidden;