[ios] Fix uses of ios::ChromeBrowserState in /ios/chrome/browser/ui/settings/credit_card_scanner

The ChromeBrowserState has been moved from the "ios" namespace
to the global namespace by http://crrev.com/c/2014913. Fix the
uses from ios::ChromeBrowserState to ChromeBrowserState.

Also remove includes of chrome_browser_state_forward.h and use
a simple forward declaration instead (since the old name is no
longer necessary).

This CL was uploaded by git cl split.

R=javierrobles@chromium.org

Bug: 1042208
Change-Id: I951945d01287beb4c2f57357da575ec093fa89e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2015170
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734543}

ios/chrome/browser/ui/settings/credit_card_scanner/credit_card_scanner_coordinator.h

@@ -23,8 +23,7 @@ API_AVAILABLE(ios(13.0))
     NS_UNAVAILABLE;
 
 - (instancetype)initWithBaseViewController:(UIViewController*)viewController
-                              browserState:
-                                  (ios::ChromeBrowserState*)browserState
+                              browserState:(ChromeBrowserState*)browserState
     NS_UNAVAILABLE;
 
 - (instancetype)initWithBaseViewController:(UIViewController*)viewController