[CrOS Wallpaper] Fix CSS so that navbar appears correctly.

Currently the navbar is too long and some image titles are prematurely
cutoff.  This CL ensures the navbar is up to specs.

screenshots (after):
https://screenshot.googleplex.com/ZYi94ycYreo (english ltr)
https://screenshot.googleplex.com/cVFMK99HuDv (arabic rtl)

Specs:
https://drive.google.com/open?id=10Mwipz5IFvlf_bOVSu7JnTS2bKckrGBp

Bug: 1016964
Change-Id: Ibba8c02abf66249b6f2a42fd9af7781951db8b47
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1874817Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708771}

chrome/browser/resources/chromeos/wallpaper_manager/css/wallpaper_manager.css

@@ -420,9 +420,9 @@ body:not([surprise-me-disabled]) [visibleif~='surprise-me-disabled'] {
   box-shadow: 0 24px 48px rgba(0, 0, 0, 0.24), 0 0 24px rgba(0, 0, 0, 0.12);
   display: flex;
   height: 48px;
+  position: absolute;
   top: 0;
   visibility: hidden;  /* Need this for correct positioning. */
-  width: 100%;
 }
 
 .preview-mode:not(.wallpaper-set-successfully) #top-header {
@@ -460,7 +460,7 @@ body:not([surprise-me-disabled]) [visibleif~='surprise-me-disabled'] {
 
 .top-header-contents #image-title {
   color: rgb(32, 33, 36);
-  max-width: 148px;
+  max-width: 786px;
   overflow: hidden;
   padding-inline-end: 8px;
   text-overflow: ellipsis;
@@ -477,6 +477,7 @@ body:not([surprise-me-disabled]) [visibleif~='surprise-me-disabled'] {
   color: rgb(128, 134, 139);
   max-width: 312px;
   overflow: hidden;
+  padding-inline-end: 16px;
   padding-inline-start: 8px;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -496,8 +497,7 @@ body:not([surprise-me-disabled]) [visibleif~='surprise-me-disabled'] {
 
 .top-header-contents .more-options {
   display: flex;
-  position: absolute;
-  right: 8px;
+  margin-inline-end: 8px;
 }
 
 html[dir='rtl'] .top-header-contents .more-options {
@@ -522,7 +522,7 @@ html[dir='rtl'] .top-header-contents .more-options {
   background-color: #fff;
   color: rgb(26, 115, 232);
   display: none;
-  margin-top: -8px;
+  margin: -8px 0 8px 0;
   padding: 8px 24px;
 }