Fix for issue where line wraps incorrectly on fixed width diff view

A css rule that was added for the full width diff caused lines to wrap
incorrectly. I've adjusted the style so that it is only present with
the full-width class.

Bug: Issue 4870
Change-Id: Ie94d0a06a125efb9fe7fa25ff7f2d45f54331d64

polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html

diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
index 0816501..855f45a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
@@ -90,6 +90,10 @@
       .full-width {
         width: 100%;
       }
+      .full-width .contentText {
+        white-space: pre-wrap;
+        word-wrap: break-word;
+      }
       .lineNum,
       .content {
         /* Set font size based the user's diff preference. */
@@ -138,10 +142,6 @@
         background-color: #fef;
         color: #849;
       }
-      .contentText {
-        white-space: pre-wrap;
-        word-wrap: break-word;
-      }
       .contextControl gr-button {
         display: inline-block;
         font-family: var(--monospace-font-family);