Remove command palette POC (#24044)

* Revert "POC: Cross-team recent search (#20027)"

This reverts commit aa59c28b04, preserving
a few code tidyings unrelated to the original PR.

* Revert "Add feature flag for command palette (#20011)"

This reverts commit c78c5ce3f3.

server/public/model/post.go

@@ -77,11 +77,6 @@ const (
 	PostPropsPersistentNotifications = "persistent_notifications"
 )
 
-const (
-	ModifierMessages string = "messages"
-	ModifierFiles    string = "files"
-)
-
 type Post struct {
 	Id         string `json:"id"`
 	CreateAt   int64  `json:"create_at"`
@@ -197,7 +192,6 @@ type SearchParameter struct {
 	Page                   *int    `json:"page"`
 	PerPage                *int    `json:"per_page"`
 	IncludeDeletedChannels *bool   `json:"include_deleted_channels"`
-	Modifier               *string `json:"modifier"` // whether it's messages or file
 }
 
 type AnalyticsPostCountsOptions struct {