Move IDS_PASSWORD_MANAGER_EMPTY_LOGIN to component resources

The string "(No username)" is currently used in the password manager bubble, but became useful also for password-field suggestions introduced by https://codereview.chromium.org/773573004/.

This CL ensures, that when a user gets a suggestions pop-up in a password field, and has an empty username saved with a password, the suggestion explicitly mentions the username is missing, instead of displaying a blank suggestion. This is consistent with the bubble.

As a side-effect, the corresponding string is moved from chrome to components resources.

BUG=442191,410963
[email protected]

Review URL: https://codereview.chromium.org/785233009

Cr-Commit-Position: refs/heads/master@{#308635}
diff --git a/components/components_strings.grd b/components/components_strings.grd
index 0766ab30..277d25c 100644
--- a/components/components_strings.grd
+++ b/components/components_strings.grd
@@ -174,6 +174,7 @@
       <part file="error_page_strings.grdp" />
       <part file="google_strings.grdp" />
       <part file="omnibox_strings.grdp" />
+      <part file="password_manager_strings.grdp" />
       <part file="pdf_strings.grdp" />
       <part file="policy_strings.grdp" />
       <part file="translate_strings.grdp" />