MM-44088: Add teamID filter to channelMembers (#20176)

We add 2 new params to channel members query.
1. Filter by teamId.
2. Negate that filter.

We include some more optimizations like:
- Moved the team role checks inside the dataloader.
- Moved the channel pretty name computation inside the loader.

Now that we load less data on initial load, we can reduce
the concurrency requirement to be a bit on the safer side.

```release-note
NONE
```

store/sqlstore/channel_store.go

@@ -2814,7 +2814,7 @@ func (s SqlChannelStore) GetMembersForUser(teamID string, userID string) (model.
 	return dbMembers.ToModel(), nil
 }
 
-func (s SqlChannelStore) GetMembersForUserWithCursor(userID, afterChannel, afterUser string, limit, lastUpdateAt int) (model.ChannelMembers, error) {
+func (s SqlChannelStore) GetMembersForUserWithCursor(userID, teamID string, opts *store.ChannelMemberGraphQLSearchOpts) (model.ChannelMembers, error) {
 	query := s.getQueryBuilder().
 		Select("ChannelMembers.*",
 			"TeamScheme.DefaultChannelGuestRole TeamSchemeDefaultGuestRole",
@@ -2834,20 +2834,36 @@ func (s SqlChannelStore) GetMembersForUserWithCursor(userID, afterChannel, after
 		}).
 		OrderBy("ChannelId, UserId ASC").
 		// The limit is verified at the GraphQL layer.
-		Limit(uint64(limit))
+		Limit(uint64(opts.Limit))
 
-	if afterChannel != "" && afterUser != "" {
+	if teamID != "" {
+		if opts.ExcludeTeam {
+			// Exclude this team and DM/GMs
+			query = query.Where(sq.And{
+				sq.NotEq{"Channels.TeamId": teamID},
+				sq.NotEq{"Channels.TeamId": ""},
+			})
+		} else {
+			// Include this team and DM/GMs
+			query = query.Where(sq.Or{
+				sq.Eq{"Channels.TeamId": teamID},
+				sq.Eq{"Channels.TeamId": ""},
+			})
+		}
+	}
+
+	if opts.AfterChannel != "" && opts.AfterUser != "" {
 		query = query.Where(sq.Or{
-			sq.Gt{"ChannelMembers.ChannelId": afterChannel},
+			sq.Gt{"ChannelMembers.ChannelId": opts.AfterChannel},
 			sq.And{
-				sq.Eq{"ChannelMembers.ChannelId": afterChannel},
-				sq.Gt{"ChannelMembers.UserId": afterUser},
+				sq.Eq{"ChannelMembers.ChannelId": opts.AfterChannel},
+				sq.Gt{"ChannelMembers.UserId": opts.AfterUser},
 			},
 		})
 	}
 
-	if lastUpdateAt != 0 {
-		query = query.Where(sq.GtOrEq{"ChannelMembers.LastUpdateAt": lastUpdateAt})
+	if opts.LastUpdateAt != 0 {
+		query = query.Where(sq.GtOrEq{"ChannelMembers.LastUpdateAt": opts.LastUpdateAt})
 	}
 
 	queryString, args, err := query.ToSql()