GraphQL: Unlock goroutine throttle to match batch capacity (#20146)

We were throttling the amount of concurrent resolvers
at a given time. The idea behind this was to avoid overloading
the database with too many requests.

However, with the introduction of dataloaders, this limitation
actually becomes a bottleneck because all DB calls are actually
batched, so we are unnecessarily throttling the amount of
items that can be processed in a single batch.

The only caveat with this is that now all resolvers
need to backed by dataloaders, or otherwise not be queried
as part of a loop.

In a subsequent PR, we will be removing channel stats
from under channel to be a top-level object to be returned
for a given channel.

```release-note
NONE
```

app/bot.go

@@ -101,7 +101,7 @@ func (a *App) GetWarnMetricsBot() (*model.Bot, *model.AppError) {
 		Inactive: false,
 	}
 
-	sysAdminList, err := a.GetUsers(userOptions)
+	sysAdminList, err := a.GetUsersFromProfiles(userOptions)
 	if err != nil {
 		return nil, err
 	}
@@ -130,7 +130,7 @@ func (a *App) GetSystemBot() (*model.Bot, *model.AppError) {
 		Inactive: false,
 	}
 
-	sysAdminList, err := a.GetUsers(userOptions)
+	sysAdminList, err := a.GetUsersFromProfiles(userOptions)
 	if err != nil {
 		return nil, err
 	}
@@ -485,7 +485,7 @@ func (a *App) notifySysadminsBotOwnerDeactivated(c *request.Context, userID stri
 	// get sysadmins
 	var sysAdmins []*model.User
 	for {
-		sysAdminsList, err := a.GetUsers(userOptions)
+		sysAdminsList, err := a.GetUsersFromProfiles(userOptions)
 		if err != nil {
 			return err
 		}