Only call handle method on multihandler inner handler if enabled (#43613)

### What does this PR do?
Update `MultiHandler` to only call a inner handler's `Handle` method if this `Handler` is enabled.  

### Motivation
The [documentation](https://pkg.go.dev/log/slog#Handler) of the `Handle` method explicitly says that the method should only be called when enabled.  
```
// Handle handles the Record.
// It will only be called when Enabled returns true.
```

### Describe how you validated your changes
CI

### Additional Notes


Co-authored-by: pierre.gimalac <[email protected]>

Author: pgimalac

pkg/util/log/slog/handlers/multi.go

@@ -32,8 +32,10 @@ func NewMulti(handlers ...slog.Handler) slog.Handler {
 func (h *multi) Handle(ctx context.Context, r slog.Record) error {
 	var errs []error
 	for _, handler := range h.handlers {
-		if err := handler.Handle(ctx, r); err != nil {
-			errs = append(errs, err)
+		if handler.Enabled(ctx, r.Level) {
+			if err := handler.Handle(ctx, r); err != nil {
+				errs = append(errs, err)
+			}
 		}
 	}
 	return errors.Join(errs...)

pkg/util/log/slog/handlers/multi_test.go

@@ -223,3 +223,25 @@ func TestMultiHandlerChaining(t *testing.T) {
 	err := handler.Handle(context.Background(), record)
 	assert.NoError(t, err)
 }
+
+func TestMultiHandlerOnlyCallsEnabledHandlers(t *testing.T) {
+	inner1 := newMockInnerHandler()
+	inner1.enabled = true
+	inner2 := newMockInnerHandler()
+	inner2.enabled = false
+	inner3 := newMockInnerHandler()
+	inner3.enabled = true
+
+	handler := NewMulti(inner1, inner2, inner3)
+
+	record := slog.NewRecord(time.Now(), slog.LevelInfo, "test message", 0)
+	err := handler.Handle(context.Background(), record)
+
+	// Should not return error
+	assert.NoError(t, err)
+
+	// Only enabled handlers should have Handle called
+	assert.Equal(t, 1, inner1.recordCount())
+	assert.Equal(t, 0, inner2.recordCount())
+	assert.Equal(t, 1, inner3.recordCount())
+}