Move Cluster.apiUrl to seperate injectable (#7354)

* Refactor out Cluster.apiUrl to direct reading

- Should help prevent using stale data

- Removes some uses of synchronous FS operations

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* Fix type errors

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* Rename helper function to better communicate intent

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* Improve prometheus handler tests to override less things

Signed-off-by: Sebastian Malton <sebastian@malton.name>

---------

Signed-off-by: Sebastian Malton <sebastian@malton.name>

packages/core/src/common/kube-helpers/load-validated-config-from-file.injectable.ts

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) OpenLens Authors. All rights reserved.
+ * Licensed under MIT License. See LICENSE in root directory for more information.
+ */
+import { getInjectable } from "@ogre-tools/injectable";
+import type { Cluster } from "../cluster/cluster";
+import readFileInjectable from "../fs/read-file.injectable";
+import type { ValidateKubeConfigResult } from "../kube-helpers";
+import { loadValidatedConfig } from "../kube-helpers";
+import resolveTildeInjectable from "../path/resolve-tilde.injectable";
+
+export type LoadValidatedClusterConfig = (cluster: Cluster) => Promise<ValidateKubeConfigResult>;
+
+const loadValidatedClusterConfigInjectable = getInjectable({
+  id: "load-validated-cluster-config",
+  instantiate: (di): LoadValidatedClusterConfig => {
+    const readFile = di.inject(readFileInjectable);
+    const resolveTilde = di.inject(resolveTildeInjectable);
+
+    return async (cluster) => {
+      const data = await readFile(resolveTilde(cluster.kubeConfigPath.get()));
+
+      return loadValidatedConfig(data, cluster.contextName.get());
+    };
+  },
+});
+
+export default loadValidatedClusterConfigInjectable;