Do not hold any tasks by default and no other terminals

[SomeoneToIgnore]

Reverts the last bits of https://github.com/zed-industries/zed/pull/13898 , avoiding any hold: true defaults for any Alacritty terminal tasks.

With hold: true, cargo run and other commands "hang" on ctrl-c signal and never allow to be restarted - this is quite badly breaks the workflow working on macOS, the PR aims to keep the behavior as the same.

Instead, task templates had received another parameter to do that in cases when it's needed. @osiewicz do you have better ideas on incorporating this into the task template? Maybe it's time to rework the allow_concurrent_runs bits somehow?

Release Notes:

• Fixed tasks on Linux not finishing properly after ctrl-c