Always attempt desktop discovery, even if LDAP is not ready

If Teleport loses it's connection to the LDAP server, it will
attempt to initiate a new condition when:

1. The user tries to connect to a desktop and Teleport fails
   to obtain the user's SID.
2. The periodic desktop discovery routine attempts to search
   LDAP for desktops.

In some circumstances, #2 never gets the chance to apply, since
discovery is skipped when LDAP is not ready. Additionally, if
LDAP is not ready, then you can't connect to a desktop, so #1
can't happen either, which means Teleport won't connect again
until it is restarted.

lib/srv/desktop/discovery.go

@@ -99,11 +99,6 @@ func (s *WindowsService) ldapSearchFilter() string {
 
 // getDesktopsFromLDAP discovers Windows hosts via LDAP
 func (s *WindowsService) getDesktopsFromLDAP() map[string]types.WindowsDesktop {
-	if !s.ldapReady() {
-		s.cfg.Logger.WarnContext(context.Background(), "skipping desktop discovery: LDAP not yet initialized")
-		return nil
-	}
-
 	filter := s.ldapSearchFilter()
 	s.cfg.Logger.DebugContext(context.Background(), "searching for desktops", "filter", filter)
 
@@ -250,7 +245,11 @@ func (s *WindowsService) lookupDesktop(ctx context.Context, hostname string) ([]
 
 // ldapEntryToWindowsDesktop generates the Windows Desktop resource
 // from an LDAP search result
-func (s *WindowsService) ldapEntryToWindowsDesktop(ctx context.Context, entry *ldap.Entry, getHostLabels func(string) map[string]string) (types.WindowsDesktop, error) {
+func (s *WindowsService) ldapEntryToWindowsDesktop(
+	ctx context.Context,
+	entry *ldap.Entry,
+	getHostLabels func(string) map[string]string,
+) (types.WindowsDesktop, error) {
 	hostname := entry.GetAttributeValue(windows.AttrDNSHostName)
 	if hostname == "" {
 		attrs := make([]string, len(entry.Attributes))