Description of problem:
The proxy provider is not working with enumerate=true when trying to fetch all
groups

Version-Release number of selected component (if applicable):
sssd-2.0.0-36.el8.x86_64

How reproducible:
always


Steps to Reproduce:
1. Configure sssd with a proxy provider
2. Fetch all groups using '# getent group'


Actual results:
Fetching all groups take too much time(approx 80 to 90 seconds)

Expected results:
Should not take that much time to fetch all groups.

Additional info:
# cat /etc/sssd/sssd.conf
[sssd]
config_file_version = 2
domains = proxy, ldap
sbus_timeout = 30
services = nss, pam

[domain/proxy]
auth_provider = proxy
cache_credentials = True
enumerate = TRUE
id_provider = proxy
debug_level = 0xFFF0
proxy_lib_name = ldap
proxy_pam_target = sssdproxyldap
filter_users = puser10
use_fully_qualified_names = True

[domain/ldap]
id_provider = ldap
auth_provider = ldap
cache_credentials = FALSE
ldap_search_base = dc=bos,dc=redhat,dc=com
chpass_provider = ldap
ldap_id_use_start_tls = True
debug_level = 0xFFF0
min_id  = 1000
enumerate = TRUE
ldap_uri = ldaps://server.example.com:636
ldap_tls_cacert = /etc/openldap/certs/cacert2.pem

[nss]
filter_groups = root
filter_users = root
debug_level = 9

[pam]