Description of problem:

Let say, the satellite has 2 lifecycle environment 'Development' and 'Testing', only Development LE is assigned and synced to the capsule. After registering a client through the capsule, I can assign 'Testing' LE to the client system in the content host profile. After that, 'yum repolist' fails with 404 error like below:

~~~~~~~~~~~~~~~
[root@client ~]# yum repolist
Loaded plugins: enabled_repos_upload, package_upload, product-id, search-disabled-repos, subscription-manager
https://capsule.example.com/pulp/repos/RedHat/Development/demo/content/dist/rhel/server/7/7Server/x86_64/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.
To address this issue please refer to the below knowledge base article

https://access.redhat.com/articles/1320623

If above article doesn't help to resolve this issue please open a ticket with Red Hat Support.

https://capsule.example.com/pulp/repos/RedHat/Development/demo/content/dist/rhel/server/7/7Server/x86_64/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.
repo id repo name status
rhel-7-server-rpms/x86_64 Red Hat Enterprise Linux 7 Server (RPMs) 0
repolist: 0
Uploading Enabled Repositories Report
Loaded plugins: product-id, subscription-manager
~~~~~~~~~

We should not be able to assign the LE to the client which is not synced on the capsule or we can have a show proper error message(like 'This LE is not synced on the capsule') when trying to assign LE which is not synced on the capsule.

Version-Release number of selected component (if applicable):
Satellite 6.x

How reproducible:
Always

Steps to Reproduce:
1. Register a client through a capsule
2. Go to client profile in content host page, assign a LE which is not synced on the capsule and select a content view in that LE
3. Execute below command on the client:

1. subscription-manager refresh
2. yum clean all; yum repolist

QE Tracker for https://issues.redhat.com/browse/SAT-1996
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1944710