Enable Launcher type to use Environmental Variables

[HardHero]

Is your feature request related to a problem? Please describe.
When using the Launcher type to "Launch agent via execution of command on controller", I try to use the command aws ssm start-session --target $NODE_NAME to create an ssh session with the AWS Systems Manager sessions. I get the following error

$ aws ssm start-session --target $NODE_NAME

An error occurred (ValidationException) when calling the StartSession operation: 1 validation error detected: Value '$NODE_NAME' at 'target' failed to satisfy constraint: Member must satisfy regular expression pattern: ^[a-zA-Z0-9_:-]{1,400}$
ERROR: Unable to launch the agent for FleetCloud i-0870f8fdcb91438b4
java.io.EOFException: unexpected stream termination
   at hudson.remoting.ChannelBuilder.negotiate(ChannelBuilder.java:459)
   at hudson.remoting.ChannelBuilder.build(ChannelBuilder.java:404)
   at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:437)
   at hudson.slaves.CommandLauncher.launch(CommandLauncher.java:170)
   at hudson.slaves.DelegatingComputerLauncher.launch(DelegatingComputerLauncher.java:64)
   at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:298)
   at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
   at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)
   at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
   at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
   at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
   at java.base/java.lang.Thread.run(Thread.java:829)
ERROR: Process terminated with exit code 254```

I realize the error tells you exactly what pattern needs to be used, but if we could just use the `$` character as well, it could potentially let this functionality execute as desired.


**Describe the solution you'd like**
On launch if the command could evaluate `$NODE_NAME` as the variable (something like i-XXXXXX) this would let us dynamically spin up jenkins agents and connect to them via AWS SSM.

**Describe alternatives you've considered**
From what I can tell, there doesn't seem to be any way to get the $NODE_NAME without using special character not allowed to be used by the regex pattern.

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