[MM-64360] Data retention: optionally preserve pinned posts (#31165)

* add new config to preserve pinned posts during data retention

* more graceful error if the pinned post was a reply in a deleted thread

server/channels/store/timerlayer/timerlayer.go

@@ -3002,10 +3002,10 @@ func (s *TimerLayerChannelMemberHistoryStore) PermanentDeleteBatch(endTime int64
 	return result, err
 }
 
-func (s *TimerLayerChannelMemberHistoryStore) PermanentDeleteBatchForRetentionPolicies(now int64, globalPolicyEndTime int64, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
+func (s *TimerLayerChannelMemberHistoryStore) PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs model.RetentionPolicyBatchConfigs, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
 	start := time.Now()
 
-	result, resultVar1, err := s.ChannelMemberHistoryStore.PermanentDeleteBatchForRetentionPolicies(now, globalPolicyEndTime, limit, cursor)
+	result, resultVar1, err := s.ChannelMemberHistoryStore.PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs, cursor)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {
@@ -6661,10 +6661,10 @@ func (s *TimerLayerPostStore) PermanentDeleteBatch(endTime int64, limit int64) (
 	return result, err
 }
 
-func (s *TimerLayerPostStore) PermanentDeleteBatchForRetentionPolicies(now int64, globalPolicyEndTime int64, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
+func (s *TimerLayerPostStore) PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs model.RetentionPolicyBatchConfigs, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
 	start := time.Now()
 
-	result, resultVar1, err := s.PostStore.PermanentDeleteBatchForRetentionPolicies(now, globalPolicyEndTime, limit, cursor)
+	result, resultVar1, err := s.PostStore.PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs, cursor)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {
@@ -10835,10 +10835,10 @@ func (s *TimerLayerThreadStore) MarkAsRead(userID string, threadID string, times
 	return err
 }
 
-func (s *TimerLayerThreadStore) PermanentDeleteBatchForRetentionPolicies(now int64, globalPolicyEndTime int64, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
+func (s *TimerLayerThreadStore) PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs model.RetentionPolicyBatchConfigs, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
 	start := time.Now()
 
-	result, resultVar1, err := s.ThreadStore.PermanentDeleteBatchForRetentionPolicies(now, globalPolicyEndTime, limit, cursor)
+	result, resultVar1, err := s.ThreadStore.PermanentDeleteBatchForRetentionPolicies(retentionPolicyBatchConfigs, cursor)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {
@@ -10851,10 +10851,10 @@ func (s *TimerLayerThreadStore) PermanentDeleteBatchForRetentionPolicies(now int
 	return result, resultVar1, err
 }
 
-func (s *TimerLayerThreadStore) PermanentDeleteBatchThreadMembershipsForRetentionPolicies(now int64, globalPolicyEndTime int64, limit int64, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
+func (s *TimerLayerThreadStore) PermanentDeleteBatchThreadMembershipsForRetentionPolicies(retentionPolicyBatchConfigs model.RetentionPolicyBatchConfigs, cursor model.RetentionPolicyCursor) (int64, model.RetentionPolicyCursor, error) {
 	start := time.Now()
 
-	result, resultVar1, err := s.ThreadStore.PermanentDeleteBatchThreadMembershipsForRetentionPolicies(now, globalPolicyEndTime, limit, cursor)
+	result, resultVar1, err := s.ThreadStore.PermanentDeleteBatchThreadMembershipsForRetentionPolicies(retentionPolicyBatchConfigs, cursor)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {