Reformat all gn files in /ios/chrome/browser/ui/list_model.

`gn format` recently changed its formatting behavior
for deps, source, and a few other elements when they
are assigned (with =) single-element lists to be consistent
with the formatting of updates (with +=) with single-element.

Now that we've rolled in a GN binary with the change,
reformat all files so that people don't get presubmit
warnings due to this.

This CL was uploaded by git cl split.

R=gambard@chromium.org

Bug: 1041419
Change-Id: Ib122628e14f65d56479d29490d5f7c36c3193d99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1997907
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731665}

ios/chrome/browser/ui/list_model/BUILD.gn

@@ -11,9 +11,7 @@ source_set("list_model") {
     "list_model.h",
     "list_model.mm",
   ]
-  deps = [
-    "//base",
-  ]
+  deps = [ "//base" ]
 }
 
 source_set("unit_tests") {