Fix crash caused by omni.kit.widget.toolbar import (#297)

In `AppLauncher`, added self._livestream >= 1 to the list of conditions
which can cause omni.kit.widget.toolbar to be loaded, as this extension
is loaded later based in AppLauncher startup to remove the 'stop'
button, and this will cause a crash if not omni.kit.widget.toolbar is
not already loaded.

This is reproducible by using any 'experience' without toolbar enabled
while having LIVESTREAM=1. An example is the `--headless` execution in
our 'Training with an RL Agent' tutorial:
`./orbit.sh -p source/standalone/workflows/sb3/train.py --task
Isaac-Cartpole-v0 --num_envs 64 --headless`

## Type of change

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applicable. -->

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

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.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
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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---------
Signed-off-by: AutonomousHansen <50837800+AutonomousHansen@users.noreply.github.com>
Co-authored-by: jsmith-bdai <142246516+jsmith-bdai@users.noreply.github.com>
Co-authored-by: Mayank Mittal <12863862+Mayankm96@users.noreply.github.com>

source/extensions/omni.isaac.orbit/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.10.3"
+version = "0.10.4"
 
 # Description
 title = "ORBIT framework for Robot Learning"

source/extensions/omni.isaac.orbit/docs/CHANGELOG.rst

 Changelog
 ---------
 
+0.10.4 (2023-12-14)
+~~~~~~~~~~~~~~~~~~~
+
+Fixed
+^^^^^
+
+* Fixed potentially breaking import of omni.kit.widget.toolbar by ensuring that
+  if live-stream is enabled, then the :mod:`omni.kit.widget.toolbar`
+  extension is loaded.
+
 0.10.3 (2023-12-12)
 ~~~~~~~~~~~~~~~~~~~
 

source/extensions/omni.isaac.orbit/omni/isaac/orbit/app.py

@@ -625,12 +625,14 @@ class AppLauncher:
         carb_settings_iface.set_bool("/orbit/offscreen_render/enabled", self._offscreen_render)
 
         # enable extensions for off-screen rendering
-        # note: depending on the app file, some extensions might not be available in it.
-        #   Thus, we manually enable these extensions to make sure they are available.
-        if self._offscreen_render or not self._headless:
-            # note: enabling extensions is order-sensitive. please do not change the order!
+        # Depending on the app file, some extensions might not be available in it.
+        # Thus, we manually enable these extensions to make sure they are available.
+        # note: enabling extensions is order-sensitive. please do not change the order!
+        if self._offscreen_render or not self._headless or self._livestream >= 1:
             # extension to enable UI buttons (otherwise we get attribute errors)
             enable_extension("omni.kit.window.toolbar")
+
+        if self._offscreen_render or not self._headless:
             # extension to make RTX realtime and path-traced renderers
             enable_extension("omni.kit.viewport.rtx")
             # extension to make HydraDelegate renderers