fix: remove unused example spot_instance_termination_watcher

[piscue]

I don't see this being used, and the only example available, it lead to confusion

[npalm]

Thx for taking the time to make a contribution. However this example is there for a reason. People can quickly see what is possible and enable it.

But I think we should find a better way how we do this for examples, because drawback is we can not verify the code in CI.

[piscue]

I did double check the adding it to our multi runner setup and the plan show us the error

An argument named "spot_instance_termination_watcher" is not expected here.

it could be that was renamed to the example after? we use instance_termination_watcher without problems

  # Enable spot termination watcher
  # spot_instance_termination_watcher = {
  #   enable = true
  # }

  # Enable to track the spot instance termination warning
  # instance_termination_watcher = {
  #   enable         = true
  # }