test(load): machine jwt profile grant (#8482)

# Which Problems Are Solved

Currently there was no load test present for machine jwt profile grant.
This test is now added

# How the Problems Are Solved

K6 test implemented.

# Additional Context

- part of https://github.com/zitadel/zitadel/issues/8352

load-test/webpack.config.js

@@ -32,14 +32,6 @@ module.exports = {
   },
   plugins: [
     new CleanWebpackPlugin(),
-    // Copy assets to the destination folder
-    // see `src/post-file-test.ts` for an test example using an asset
-    new CopyPlugin({
-      patterns: [{ 
-        from: path.resolve(__dirname, 'assets'), 
-        noErrorOnMissing: true 
-      }],
-    }),
   ],
   optimization: {
     // Don't minimize, as it's not used in the browser