APIv4 DELETE /users/{user_id}/posts/{post_id}/reactions/name (#6117)

* APIv4 DELETE /users/{user_id}/posts/{post_id}/reactions/name

* updated v3 deleteReaction endpoint

* update parameter of app.DeleteReactionForPost()

* update utils.IsValidAlphaNum, add utils.IsValidAlphaNumHyphenUnderscore, and add related tests

api4/params.go

@@ -32,6 +32,7 @@ type ApiParams struct {
 	TeamName       string
 	ChannelName    string
 	PreferenceName string
+	EmojiName      string
 	Category       string
 	Service        string
 	Page           int
@@ -111,6 +112,10 @@ func ApiParamsFromRequest(r *http.Request) *ApiParams {
 		params.PreferenceName = val
 	}
 
+	if val, ok := props["emoji_name"]; ok {
+		params.EmojiName = val
+	}
+
 	if val, err := strconv.Atoi(r.URL.Query().Get("page")); err != nil || val < 0 {
 		params.Page = PAGE_DEFAULT
 	} else {