Avoid creating a logrus logger if RBAC logging is not enabled

```bash

$ benchstat 03d741b.txt new.txt
goos: darwin
goarch: arm64
pkg: github.com/gravitational/teleport/lib/auth
                                        │ 03d741b.txt │              new.txt               │
                                        │                    sec/op                    │   sec/op     vs base               │
ListUnifiedResources/labels-12                                            281.6m ± 10%   279.1m ± 6%       ~ (p=0.631 n=10)
ListUnifiedResources/predicate_path-12                                    503.1m ±  2%   509.2m ± 1%       ~ (p=0.165 n=10)
ListUnifiedResources/predicate_index-12                                   504.9m ±  4%   494.5m ± 4%       ~ (p=0.190 n=10)
ListUnifiedResources/search_lower-12                                      335.7m ±  1%   320.4m ± 7%  -4.57% (p=0.002 n=10)
ListUnifiedResources/search_upper-12                                      340.2m ± 13%   330.9m ± 4%       ~ (p=0.105 n=10)
geomean                                                                   382.3m         375.3m       -1.83%

                                        │ 03d741b.txt │               new.txt                │
                                        │                     B/op                     │     B/op      vs base                │
ListUnifiedResources/labels-12                                           158.75Mi ± 0%   85.50Mi ± 0%  -46.14% (p=0.000 n=10)
ListUnifiedResources/predicate_path-12                                    396.9Mi ± 0%   323.7Mi ± 0%  -18.45% (p=0.000 n=10)
ListUnifiedResources/predicate_index-12                                   396.9Mi ± 0%   323.6Mi ± 0%  -18.46% (p=0.000 n=10)
ListUnifiedResources/search_lower-12                                     158.62Mi ± 0%   85.33Mi ± 0%  -46.21% (p=0.000 n=10)
ListUnifiedResources/search_upper-12                                     159.58Mi ± 0%   86.31Mi ± 0%  -45.91% (p=0.000 n=10)
geomean                                                                   229.2Mi        145.8Mi       -36.38%

                                        │ 03d741b.txt │               new.txt               │
                                        │                  allocs/op                   │  allocs/op   vs base                │
ListUnifiedResources/labels-12                                             2.412M ± 0%   1.662M ± 0%  -31.10% (p=0.000 n=10)
ListUnifiedResources/predicate_path-12                                     7.363M ± 0%   6.613M ± 0%  -10.19% (p=0.000 n=10)
ListUnifiedResources/predicate_index-12                                    7.212M ± 0%   6.462M ± 0%  -10.40% (p=0.000 n=10)
ListUnifiedResources/search_lower-12                                       3.162M ± 0%   2.412M ± 0%  -23.73% (p=0.000 n=10)
ListUnifiedResources/search_upper-12                                       3.312M ± 0%   2.562M ± 0%  -22.65% (p=0.000 n=10)
geomean                                                                    4.222M        3.376M       -20.03%
```

lib/services/role.go

@@ -2422,9 +2422,14 @@ type AccessCheckable interface {
 // It also returns a flag indicating whether debug logging is enabled,
 // allowing the RBAC system to generate more verbose errors in debug mode.
 func rbacDebugLogger() (debugEnabled bool, debugf func(format string, args ...interface{})) {
-	isDebugEnabled := log.IsLevelEnabled(log.TraceLevel)
-	log := log.WithField(teleport.ComponentKey, teleport.ComponentRBAC)
-	return isDebugEnabled, log.Tracef
+	debugEnabled = log.IsLevelEnabled(log.TraceLevel)
+	debugf = func(format string, args ...interface{}) {}
+
+	if debugEnabled {
+		debugf = log.WithField(teleport.ComponentKey, teleport.ComponentRBAC).Tracef
+	}
+
+	return
 }
 
 func (set RoleSet) checkAccess(r AccessCheckable, traits wrappers.Traits, state AccessState, matchers ...RoleMatcher) error {