[MM-21919] Add use_channel_mentions permission (#13781)

* MM-21919 Add channel_mention permission

* MM-21919 Fix emojis migration test

* Enforce Channel Mentions on the in the posts api

* MM-21919 Rename permission to use_channel_mentions

Allow posts with channel mentions to still be posted without the permission just don't send notifications to users

* MM-21919 Add tests for a post with @all and @here

* MM-21919 Add use channel mentions to all roles that have create post

* MM-21919 Update app_test to include use_channel_mentions permission in default permissions

model/role.go

@@ -187,6 +187,7 @@ func MakeDefaultRoles() map[string]*Role {
 			PERMISSION_UPLOAD_FILE.Id,
 			PERMISSION_EDIT_POST.Id,
 			PERMISSION_CREATE_POST.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 			PERMISSION_USE_SLASH_COMMANDS.Id,
 		},
 		SchemeManaged: true,
@@ -205,6 +206,7 @@ func MakeDefaultRoles() map[string]*Role {
 			PERMISSION_UPLOAD_FILE.Id,
 			PERMISSION_GET_PUBLIC_LINK.Id,
 			PERMISSION_CREATE_POST.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 			PERMISSION_USE_SLASH_COMMANDS.Id,
 		},
 		SchemeManaged: true,
@@ -253,6 +255,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.team_post_all.description",
 		Permissions: []string{
 			PERMISSION_CREATE_POST.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 		},
 		SchemeManaged: false,
 		BuiltIn:       true,
@@ -264,6 +267,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.team_post_all_public.description",
 		Permissions: []string{
 			PERMISSION_CREATE_POST_PUBLIC.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 		},
 		SchemeManaged: false,
 		BuiltIn:       true,
@@ -323,6 +327,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.system_post_all.description",
 		Permissions: []string{
 			PERMISSION_CREATE_POST.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 		},
 		SchemeManaged: false,
 		BuiltIn:       true,
@@ -334,6 +339,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.system_post_all_public.description",
 		Permissions: []string{
 			PERMISSION_CREATE_POST_PUBLIC.Id,
+			PERMISSION_USE_CHANNEL_MENTIONS.Id,
 		},
 		SchemeManaged: false,
 		BuiltIn:       true,