Description Florian Best 2024-03-05 18:24:52 CET

One leaking LDAP connection which is opened for the logged in user is created and not closed as LDAP connections are cached.
But the cache indicator is broken and is bound to the request instead of the session.
Therefore every new request opens a new LDAP connection.

Reproducer:
```python
import objgraph
import univention.management.console.message

x = univention.management.console.message.Request('foo')
y = univention.management.console.message.Request('foo')
x.user_dn = y.user_dn = 'uid=Administrator,cn=users,dc=school,dc=dev'
x.password = y.password = 'univention'

lo = x.get_user_ldap_connection()
print(objgraph.count('univention.admin.uldap.access'))  # prints 1

lo2 = x.get_user_ldap_connection()
lo2 = y.get_user_ldap_connection()
print(objgraph.count('univention.admin.uldap.access'))  # prints 2 (or 3), should print 1
```