fix: relax parsing of SCIM user 'active' flag to improve compatibility (#9296)

# Which Problems Are Solved
- Microsoft Entra invokes the user patch endpoint with `"active":
"True"` / `"active": "False"` when patching a user. This is a well-known
bug in MS Entra (see
[here](https://learn.microsoft.com/en-us/entra/identity/app-provisioning/application-provisioning-config-problem-scim-compatibility)),
but the bug fix has not landed yet and/or the feature flag does not
work.

# How the Problems Are Solved
- To ensure compatibility with MS Entra, the parsing of the the boolean
active flag of the scim user is relaxed and accepts strings in any
casing that resolve to `true` or `false` as well as raw boolean values.

# Additional Context
Part of https://github.com/zitadel/zitadel/issues/8140

internal/api/scim/integration_test/users_get_test.go

@@ -9,7 +9,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/muhlemmer/gu"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/text/language"
@@ -112,7 +111,7 @@ func TestGetUser(t *testing.T) {
 				PreferredLanguage: language.Make("en-US"),
 				Locale:            "en-US",
 				Timezone:          "America/Los_Angeles",
-				Active:            gu.Ptr(true),
+				Active:            schemas.NewRelaxedBool(true),
 				Emails: []*resources.ScimEmail{
 					{
 						Value:   "bjensen@example.com",