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/testdata/users_update_test_full.json

@@ -134,6 +134,14 @@
       "op": "replace",
       "path": "password",
       "value": "Password2!"
+    },
+    // replace active state
+    {
+      "op": "replace",
+      "path": "active",
+      // quoted uppercase bool
+      // (ensure compatibility with Microsoft Entra)
+      "value": "True"
     }
   ]
 }