Add read_channel_content permission (#24118)

* Add read_channel_content permission

* fix tests

* update system console default permissions per role

* add read_channel_content to e2e defaultRolesPermissions

* Migration to include custom roles

* change deprecated isNotExactRole for isNotRole

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/role.go

@@ -749,6 +749,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.channel_guest.description",
 		Permissions: []string{
 			PermissionReadChannel.Id,
+			PermissionReadChannelContent.Id,
 			PermissionAddReaction.Id,
 			PermissionRemoveReaction.Id,
 			PermissionUploadFile.Id,
@@ -766,6 +767,7 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.channel_user.description",
 		Permissions: []string{
 			PermissionReadChannel.Id,
+			PermissionReadChannelContent.Id,
 			PermissionAddReaction.Id,
 			PermissionRemoveReaction.Id,
 			PermissionManagePublicChannelMembers.Id,