chore: migrate three packages to MSW v2

Migrates test files in config-loader, events-node and kubernetes-react
packages from MSW 1.x to MSW 2.x API to fix compatibility issues with
Jest 30 and JSDOM v26.

Changes:
- Updated msw dependency from ^1.0.0 to ^2.0.0
- Changed imports from `rest` to `http` and `HttpResponse`
- Converted handler syntax from `res(ctx.*)` to `HttpResponse.*`
- Changed `toStrictEqual` to `toEqual` for response assertions

Affected packages:
- @backstage/config-loader
- @backstage/plugin-events-node
- @backstage/plugin-kubernetes-react

Signed-off-by: Johan Persson <johanopersson@gmail.com>

yarn.lock

@@ -3498,7 +3498,7 @@ __metadata:
     json-schema-traverse: "npm:^1.0.0"
     lodash: "npm:^4.17.21"
     minimist: "npm:^1.2.5"
-    msw: "npm:^1.0.0"
+    msw: "npm:^2.0.0"
     typescript-json-schema: "npm:^0.67.0"
     yaml: "npm:^2.0.0"
     zen-observable: "npm:^0.10.0"
@@ -5800,7 +5800,7 @@ __metadata:
     content-type: "npm:^1.0.5"
     cross-fetch: "npm:^4.0.0"
     express: "npm:^4.22.0"
-    msw: "npm:^1.0.0"
+    msw: "npm:^2.0.0"
     uri-template: "npm:^2.0.0"
   languageName: unknown
   linkType: soft
@@ -6048,7 +6048,7 @@ __metadata:
     kubernetes-models: "npm:^4.3.1"
     lodash: "npm:^4.17.21"
     luxon: "npm:^3.0.0"
-    msw: "npm:^1.3.1"
+    msw: "npm:^2.0.0"
     react: "npm:^18.0.2"
     react-dom: "npm:^18.0.2"
     react-router-dom: "npm:^6.3.0"