Fixes modules being loaded when defined in extension.toml file (#237)

# Description

In the extension.toml for the isaaclab_rl and isaaclab_tasks extensions,
pipapi and module tags are specified for the various RL libraries. These
tags introduce an import call that loads these packages.

The SKRL package in particular will initialize torch.distributed if
running distributed training, causing errors if other RL libraries are
being used, since other libraries will try to initialize
torch.distributed again in its own code.

This should ideally be fixed from the SKRL side.


## Type of change

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applicable. -->

- Bug fix (non-breaking change which fixes an issue)


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## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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source/isaaclab_rl/config/extension.toml

@@ -16,26 +16,5 @@ keywords = ["robotics", "rl", "wrappers", "learning"]
 "isaaclab_assets" = {}
 "isaaclab_tasks" = {}
 
-[python.pipapi]
-requirements = [
-    "h5py",
-    "tensorboard",
-    "stable-baselines3>=2.1",
-    "rl-games==1.6.1",
-    "rsl-rl@git+https://github.com/leggedrobotics/rsl_rl.git",
-    "skrl>=1.3.0"
-]
-
-modules = [
-    "h5py",
-    "tensorboard",
-    "stable_baselines3",
-    "rl_games",
-    "rsl_rl",
-    "skrl"
-]
-
-use_online_index=true
-
 [[python.module]]
 name = "isaaclab_rl"

source/isaaclab_tasks/config/extension.toml

@@ -15,26 +15,5 @@ keywords = ["robotics", "rl", "il", "learning"]
 "isaaclab" = {}
 "isaaclab_assets" = {}
 
-[python.pipapi]
-requirements = [
-    "h5py",
-    "tensorboard",
-    "stable-baselines3>=2.1",
-    "rl-games==1.6.1",
-    "rsl-rl@git+https://github.com/leggedrobotics/rsl_rl.git",
-    "skrl>=1.3.0"
-]
-
-modules = [
-    "h5py",
-    "tensorboard",
-    "stable_baselines3",
-    "rl_games",
-    "rsl_rl",
-    "skrl"
-]
-
-use_online_index=true
-
 [[python.module]]
 name = "isaaclab_tasks"