[Managed Session] Adjust width of 'Choose language and keyboard' field

Field text was changed in a previous CL which increased the width of the text,
but the field width wasn't adjusted for this thereby creating a visual artifact.

Screenshot before adjusting: https://screenshot.googleplex.com/cEJmBzFpvJO.png

Screenshot after adjusting: https://screenshot.googleplex.com/Pbe9mXmp1RK.png

Bug: 865947
Change-Id: Ia12ad95bc0c96e540e0aa7ee1fa9949803efe97c
Reviewed-on: https://chromium-review.googlesource.com/1196583Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Ivan Šandrk <isandrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587690}

ash/login/ui/login_expanded_public_account_view.cc

@@ -58,7 +58,7 @@ constexpr SkColor kArrowButtonColor = SkColorSetARGB(0xFF, 0x42, 0x85, 0xF4);
 
 constexpr int kDropDownIconSizeDp = 16;
 constexpr int kArrowButtonSizeDp = 40;
-constexpr int kAdvancedViewButtonWidthDp = 174;
+constexpr int kAdvancedViewButtonWidthDp = 190;
 constexpr int kAdvancedViewButtonHeightDp = 16;
 constexpr int kSelectionBoxWidthDp = 178;
 constexpr int kSelectionBoxHeightDp = 28;