feat(oauth): send feature flag to frontend (#80120)

There's no org [where this feature flag is being
checked](https://github.com/getsentry/getsentry/blob/master/static/getsentry/gsAdmin/views/instanceLevelOAuth/components/newInstanceLevelOAuthClient.tsx#L24)
so enabling it through the config. This basically makes it available in
the Config object on the frontend

src/sentry/features/temporary.py

@@ -584,3 +584,11 @@ def register_temporary_features(manager: FeatureManager):
         FeatureHandlerStrategy.FLAGPOLE,
         api_expose=True,
     )
+
+    # Partner oauth
+    manager.add(
+        "organizations:scoped-partner-oauth",
+        OrganizationFeature,
+        FeatureHandlerStrategy.FLAGPOLE,
+        api_expose=False,
+    )

src/sentry/web/client_config.py

@@ -224,6 +224,13 @@ def enabled_features(self) -> Iterable[str]:
             yield "relocation:enabled"
         if features.has("system:multi-region"):
             yield "system:multi-region"
+        # TODO @athena: remove this feature flag after development is done
+        # this is a temporary hack to be able to used flagpole in a case where there's no organization
+        # availble on the frontend
+        if self.last_org and features.has(
+            "organizations:scoped-partner-oauth", self.last_org, actor=self.user
+        ):
+            yield "system:scoped-partner-oauth"
 
     @property
     def needs_upgrade(self) -> bool: