Rename translate force trigger on english pref

This resets the backoff state in order to re-run the experiment in India

Bug: 936028
Change-Id: Id55c80ce6ff3d4b4c824a4c1833a5f5d3c03d202
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504129
Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Commit-Queue: anthonyvd <anthonyvd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637861}

components/translate/core/browser/translate_prefs.cc

@@ -38,7 +38,7 @@
 namespace translate {
 
 const char kForceTriggerTranslateCount[] =
-    "translate_force_trigger_on_english_count_for_backoff";
+    "translate_force_trigger_on_english_count_for_backoff_1";
 const char TranslatePrefs::kPrefTranslateSiteBlacklistDeprecated[] =
     "translate_site_blacklist";
 const char TranslatePrefs::kPrefTranslateSiteBlacklistWithTime[] =