[Nearby] Add css to format dictionaries to be more readable.

Add style to make dictionaries passed as NS_LOGS more readable on the
debug page.

Bug: 1093634
Change-Id: Iae95b101a1ad00af5e0267d1aa444f33fe670a56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368496Reviewed-by: Josh Nohle <nohle@chromium.org>
Commit-Queue: Juliet Levesque <julietlevesque@google.com>
Cr-Commit-Position: refs/heads/master@{#800446}

chrome/browser/resources/nearby_internals/logging_tab.html

@@ -7,6 +7,7 @@
     display: flex;
     flex-direction: column;
     height: 100%;
+    white-space: pre-wrap;
   }
 
   log-object {