Access control management via labels not fault tolerant

[m-a-v]

Bug description
If user names are entered multiple times or with spaces in the docker compose file, the access rights are not set correctly.

From #3337:
There seem to be problems with double entries. E.g.
- "io.portainer.accesscontrol.users=bob,adam,bob"

This changes the ownership of the group to restricted. But neither bob nor adam are listed.

Probably, the strings should be trimmed. Otherwise adam will not have access to the resource.
- "io.portainer.accesscontrol.users=bob, adam"

Expected behavior
Both users adam and bob should get access.

[ghost]

Seems this is also not tolerant of spaces as "io.portainer.accesscontrol.users=bob, adam" only restricts to bob

[m-a-v]

Seems this is also not tolerant of spaces as "io.portainer.accesscontrol.users=bob, adam" only restricts to bob

See above. I've already mentioned this ... (the strings should be trimmed)

[ghost]

Reproduced on 1.23.2.