[MM-42191]: Include deleted posts (#19985)

* MM-42191: Include deleted posts: Add includeDeleted query parameter for getPostsForChannel

* MM-42191: Fix error typo for includeDeleted query parameter

* MM-42191: Include deleted posts: Set permission error when deleted posts are requested by non system admins

* MM-42191: Include deleted posts: Refactor replyCountSubQuery and conditions when includeDeleted is not presented, refactor getRootPosts

* MM-42191: Include deleted posts: Refactor getRootPosts function along with skipFetchThreads and includeDeleted

* MM-42191: Include deleted posts: Rename includeDeleted to include_deleted param

* MM-42191: Include deleted posts: Fix failed posts unit tests

* MM-42191: Include deleted posts: Add missing include deleted option in multiple queries

* MM-42191: Include deleted posts: Add tests for include deleted option in TestGetPostsForChannel, TestGetPostsBefore, TestGetPostsAfter

* MM-42191: include deleted posts: Add tests cases for post store test

* MM-42191: Include deleted posts: Add extra unit test to ensure not returning deleted posts when IncludeDelete is false

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

model/client4.go

@@ -3925,11 +3925,15 @@ func (c *Client4) GetPostThreadWithOpts(postID string, etag string, opts GetPost
 }
 
 // GetPostsForChannel gets a page of posts with an array for ordering for a channel.
-func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v", page, perPage)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err
@@ -4050,11 +4054,14 @@ func (c *Client4) GetPostsSince(channelId string, time int64, collapsedThreads b
 }
 
 // GetPostsAfter gets a page of posts that were posted after the post provided.
-func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&after=%v", page, perPage, postId)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err
@@ -4071,11 +4078,14 @@ func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, eta
 }
 
 // GetPostsBefore gets a page of posts that were posted before the post provided.
-func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&before=%v", page, perPage, postId)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err