MM-42268: We add more fields to Channel and Team (#19675)

Also added sessions as part of the user object

https://mattermost.atlassian.net/browse/MM-42268

```release-note
NONE
```

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/channel.go

@@ -178,6 +178,14 @@ func (o *Channel) DeleteAt_() float64 {
 	return float64(o.DeleteAt)
 }
 
+func (o *Channel) LastPostAt_() float64 {
+	return float64(o.LastPostAt)
+}
+
+func (o *Channel) TotalMsgCount_() float64 {
+	return float64(o.TotalMsgCount)
+}
+
 func (o *Channel) DeepCopy() *Channel {
 	copy := *o
 	if copy.SchemeId != nil {

model/session.go

@@ -218,3 +218,11 @@ func (s *Session) GetCSRF() string {
 
 	return s.Props["csrf"]
 }
+
+func (s *Session) CreateAt_() float64 {
+	return float64(s.CreateAt)
+}
+
+func (s *Session) ExpiresAt_() float64 {
+	return float64(s.ExpiresAt)
+}

model/team.go

@@ -251,3 +251,16 @@ func (o *Team) Patch(patch *TeamPatch) {
 func (o *Team) IsGroupConstrained() bool {
 	return o.GroupConstrained != nil && *o.GroupConstrained
 }
+
+// The following are some GraphQL methods necessary to return the
+// data in float64 type. The spec doesn't support 64 bit integers,
+// so we have to pass the data in float64. The _ at the end is
+// a hack to keep the attribute name same in GraphQL schema.
+
+func (o *Team) UpdateAt_() float64 {
+	return float64(o.UpdateAt)
+}
+
+func (o *Team) LastTeamIconUpdate_() float64 {
+	return float64(o.LastTeamIconUpdate)
+}