[SNAP] Outdated snap packages for armhf and arm64 rocketchat-server

Description:

Snap packages in https://snapcraft.io/rocketchat-server are outdated and/or channel doesn't match current AMD64 channel.

Steps to reproduce:

1. install snapd sudo apt install snapd
2. try to install rocketchat `sudo snap install rocketchat-server

Expected behavior:

Installs current stable release rocketchat-server 3.18.3 1491 3.x/stable rocketchat✓

Actual behavior:

sudo snap install rocketchat-server
error: snap "rocketchat-server" is not available on stable but is available to install on the
       following channels:

       candidate  snap install --candidate rocketchat-server
       beta       snap install --beta rocketchat-server
       edge       snap install --edge rocketchat-server

       Please be mindful pre-release channels may include features not completely tested or
       implemented. Get more information with 'snap info rocketchat-server'.

Server Setup Information:

• Operating System: Raspbian (32bit version)
• Deployment Method: snap

Start by inspecting the snap package configuration and the rocketchat-server channels on Snapcraft, then reproduce the installation on Raspbian for armhf or arm64 with snapd. Done means the current stable release is available and installs successfully on those architectures, with channels matching the AMD64 release.