Inconsistent karaf output for `addons services`

[dilyanpalauzov]

#4057 implements the openhab:addons services command in Karaf.

With OH 4.2.0M1 after openhab-cli clean-cache, I start openhab. Then Karaf shows

openhab> openhab:addons services
karaf                openHAB Distribution
marketplace          Community Marketplace
json                 Json 3rd Party Add-on Service
jar                  JAR-File add-on service

I stop openhab, then start it again and wait until everything is loaded. Then Karaf prints only:

openhab> openhab:addons services
jar                  JAR-File add-on service

I repeat the above steps from the beginning (stop oh, clean-cache, start oh, addons services, stop oh, start oh, addons services) and get consistent results: The first time four services are listed, the second time only the jar service is listed.