🐛 [#4713] Fix token exchange for BRP client

previously the submission was not passed, causing token exchange to not work

src/openforms/contrib/haal_centraal/clients/__init__.py

@@ -60,6 +60,13 @@ def get_brp_client(submission: Submission | None = None, **kwargs: Any) -> BRPCl
             f"No suitable client class configured for API version {version}"
         )
 
+    if submission:
+        kwargs.setdefault("context", {})
+        # pass submission to ensure token exchange works properly
+        # only do this if the submission is not None, to avoid unnecessary database queries
+        # done by token_exchange.auth.TokenAccessAuth
+        kwargs["context"]["submission"] = submission
+
     return build_client(
         service,
         client_factory=ClientCls,

src/openforms/prefill/contrib/haalcentraal_brp/plugin.py

@@ -13,7 +13,6 @@
 from openforms.contrib.haal_centraal.constants import BRPVersions
 from openforms.contrib.haal_centraal.models import HaalCentraalConfig
 from openforms.plugins.exceptions import InvalidPluginConfiguration
-from openforms.pre_requests.clients import PreRequestClientContext
 from openforms.submissions.models import Submission
 
 from ...base import BasePlugin
@@ -111,10 +110,7 @@ def get_prefill_values(
         identifier_role: IdentifierRoles = IdentifierRoles.main,
     ) -> dict[str, Any]:
         try:
-            client = get_brp_client(
-                submission=submission,
-                context=PreRequestClientContext(submission=submission),
-            )
+            client = get_brp_client(submission=submission)
         except NoServiceConfigured:
             return {}
 
@@ -141,10 +137,7 @@ def get_co_sign_values(
           the value is the prefill value to use for that attribute.
         """
         try:
-            client = get_brp_client(
-                submission=submission,
-                context=PreRequestClientContext(submission=submission),
-            )
+            client = get_brp_client(submission=submission)
         except NoServiceConfigured:
             return ({}, "")