Bug 1557782 - Update event listener breakpoints label to existing tools r=jlast

Per Harald's request

Differential Revision: https://phabricator.services.mozilla.com/D35538

--HG--
extra : moz-landing-system : lando

devtools/client/debugger/src/components/SecondaryPanes/index.js

@@ -350,7 +350,7 @@ class SecondaryPanes extends Component<Props, State> {
 
   getEventListenersItem(): AccordionPaneItem {
     return {
-      header: L10N.getStr("eventListenersHeader"),
+      header: L10N.getStr("eventListenersHeader1"),
       className: "event-listeners-pane",
       buttons: [],
       component: <EventListeners />,

devtools/client/locales/en-US/debugger.properties

@@ -153,9 +153,9 @@ noSourcesText=This page has no sources.
 # when there are no events.
 noEventListenersText=No event listeners to display.
 
-# LOCALIZATION NOTE (eventListenersHeader): The text to display in the events
+# LOCALIZATION NOTE (eventListenersHeader1): The text to display in the events
 # header.
-eventListenersHeader=Event listeners
+eventListenersHeader1=Event Listener Breakpoints
 
 # LOCALIZATION NOTE (noStackFramesText): The text to display in the call stack tab
 # when there are no stack frames.