Addons should show "Starting" indicator when enabled

[leigh-johnson]

Describe the bug

When you enable a service, the "Inactive" status disappears but is not replaced by a status indicator until the service is active. We should show a "Starting" status indicator when the unit state is "activating"

subject_pattern
: 
"pi.{pi_id}.dbus.org.freedesktop.systemd1.Manager.GetUnit"
unit
: 
active_state
: 
"activating"
fragment_path
: 
"/lib/systemd/system/octoprint.service"
id
: 
"octoprint.service"
load_state
: 
"loaded"
unit_file_state
: 
"enabled"

To Reproduce

What are the steps to reproduce the issue?

1. Open Mission Control dashboard
2. Disable a service
3. Enable the service
4. Notice: status indicator is blank while service is in the "activating" state

Expected behavior

A spinner should be shown, with text "Starting" when systemd units are in the activating state.

Issue.txt

-----------------------
Build Info:  |
-----------------------
IMAGE_NAME = printnanny-release-image-raspberrypi4-64-20230528210042
DISTRO_PRETTY = PrintNanny Linux 0.7.2 (Garnet)
VARIANT_NAME = PrintNanny OS Core
VARIANT_ID = core
DISTRO = printnanny
DISTRO_NAME = PrintNanny Linux
DISTRO_VERSION = 0.7.2
DISTRO_CODENAME = Garnet
ID_LIKE = BitsyLinux
HOME_URL = https://printnanny.ai
BUG_REPORT_URL = https://github.com/bitsy-ai/printnanny-os/issues
YOCTO_VERSION = 4.1.2
YOCTO_CODENAME = Langdale
MACHINE = raspberrypi4-64
TUNE_PKGARCH = cortexa72
-----------------------
Layer Revisions:      |
-----------------------
meta              = mickledore:ddb298ce894482467d82699d223c5555baad6591
meta-poky         = mickledore:ddb298ce894482467d82699d223c5555baad6591
meta-yocto-bsp    = mickledore:ddb298ce894482467d82699d223c5555baad6591
meta-oe           = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa
meta-networking   = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa
meta-python       = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa
meta-webserver    = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa
meta-initramfs    = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa
meta-bitsy        = upgrade-printnanny-rs-deps:7e551cb649692815d9ff1c300dbbaef13bae338b
meta-microcontroller = mickledore:a848733698649628d0c3e34ae04ced0ee6ce3aee
meta-neural-network = mickledore:39f06bfa582eedc8621df677bb5cf044e9481309
meta-raspberrypi  = issue-1167-raspberrypi-hq-camera:26a25492a639310bb94afd4b2b066895c9217bad
meta-swupdate     = master:19007b03a1d96eca38e12f3bbd7bb296aea50bab
meta-printnanny   = upgrade-printnanny-rs-deps:7e551cb649692815d9ff1c300dbbaef13bae338b
meta-multimedia   = mickledore-polkit-src:4321a5fd17fa2c307ca579ae76b921fb4c560bfa