[Bug]: js_binary launcher script not portable from host to exec platform

### What happened?

When RBE is used for cross-compilation, the host platform may be different from the exec platform.

In my case I have a linux_x86 host platform, so the launcher created by `ctx.actions.expand_template` here https://github.com/aspect-build/rules_js/blob/92a36f314b7841475e12a68dcd018c088f373bc2/js/private/js_binary.bzl#L481-L486
will create a file with a node path pointing to the host-resolved toolchain, with linux_x86 arch.

Now, I enable RBE and the `exec` platform is linux_arm64`. The launcher script is copied to the remote and tries to spawn node for the wrong arch, which of course fails with executable format error `cannot execute binary file ...nodejs_linux_amd64...`

### Version

Bazel 6.2.1, latest of rules_js

### How to reproduce

```shell
Tricky since you need an RBE setup with alternate architecture.
```

### Any other information?

_No response_

Read js/private/js_binary.bzl at lines 481-486, then investigate the launcher generated by ctx.actions.expand_template under an RBE setup with different host and exec architectures. Done means the launcher selects a node executable suitable for the exec platform and no longer fails with an executable format error.

Written by the indexing model from the issue text.