Bug 1860833 - optimize number of calls to getTabClient r=fxview-reviewers,sfoster

Amending the `getRecentTabs` function eliminates one of the duplicate calls to `getTabClients`. I opted for this approach as opposed
to getting tabs from clients or vice versa because that involved a larger refactor that ended up adding unnecessary noise to the
`getRecentTabs` and `getTabClients` return values. Combined with a patch by @sfoster, we have reduced the number of calls from 9 to 1.

Differential Revision: https://phabricator.services.mozilla.com/D194656

browser/components/firefoxview/syncedtabs.mjs

@@ -554,7 +554,7 @@ class SyncedTabsInView extends ViewPage {
 
   async getSyncedTabData() {
     this.devices = await lazy.SyncedTabs.getTabClients();
-    let tabs = await lazy.SyncedTabs.getRecentTabs(50, {
+    let tabs = await lazy.SyncedTabs.createRecentTabsList(this.devices, 50, {
       removeAllDupes: false,
       removeDeviceDupes: true,
     });

services/sync/modules/SyncedTabs.sys.mjs

@@ -300,6 +300,10 @@ export var SyncedTabs = {
     return this._internal.syncTabs(force);
   },
 
+  createRecentTabsList(clients, maxCount, extraParams) {
+    return this._internal._createRecentTabsList(clients, maxCount, extraParams);
+  },
+
   sortTabClientsByLastUsed(clients) {
     // First sort the list of tabs for each client. Note that
     // this module promises that the objects it returns are never