Move IDS_LEARN_MORE to components_strings.grd

To componentize sad_tab related code, move IDS_LEARN_MORE to outside of chrome.

BUG=402485
[email protected] for include fix under chrome/browser

Review URL: https://codereview.chromium.org/530963002

Cr-Commit-Position: refs/heads/master@{#292908}
diff --git a/chrome/browser/extensions/dev_mode_bubble_controller.cc b/chrome/browser/extensions/dev_mode_bubble_controller.cc
index bd2250a..c6b2ea82 100644
--- a/chrome/browser/extensions/dev_mode_bubble_controller.cc
+++ b/chrome/browser/extensions/dev_mode_bubble_controller.cc
@@ -18,6 +18,7 @@
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/feature_switch.h"
+#include "grit/components_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace extensions {