Fixes livestream mixing with sys.argv for command line arguments (#223)

Previously, additional arguments were added to command line for
initializing livestream extensions. These arguments were mistakenly
passed to downstream scripts, causing errors when the arguments are not
recognized. This fix makes sure that the additional arguments are only
passed to the kit app and not downstream apps.

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

- [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/isaaclab/app/app_launcher.py

@@ -575,14 +575,14 @@ class AppLauncher:
             )
 
         # Process livestream here before launching kit because some of the extensions only work when launched with the kit file
+        self._livestream_args = []
         if self._livestream >= 1:
-            livestream_args = []
             # Note: Only one livestream extension can be enabled at a time
             if self._livestream == 1:
                 warnings.warn(
                     "Native Livestream is deprecated. Please use WebRTC Livestream instead with --livestream 2."
                 )
-                livestream_args += [
+                self._livestream_args += [
                     '--/app/livestream/proto="ws"',
                     "--/app/livestream/allowResize=true",
                     "--enable",
@@ -593,14 +593,14 @@ class AppLauncher:
                     "omni.kit.streamsdk.plugins-4.1.1",
                 ]
             elif self._livestream == 2:
-                livestream_args += [
+                self._livestream_args += [
                     "--/app/livestream/allowResize=false",
                     "--enable",
                     "omni.kit.livestream.webrtc",
                 ]
             else:
                 raise ValueError(f"Invalid value for livestream: {self._livestream}. Expected: 1, 2 .")
-            sys.argv += livestream_args
+            sys.argv += self._livestream_args
 
         # Resolve additional arguments passed to Kit
         self._kit_args = []
@@ -648,6 +648,8 @@ class AppLauncher:
         # remove additional OV args from sys.argv
         if len(self._kit_args) > 0:
             sys.argv = [arg for arg in sys.argv if arg not in self._kit_args]
+        if len(self._livestream_args) > 0:
+            sys.argv = [arg for arg in sys.argv if arg not in self._livestream_args]
 
     def _rendering_enabled(self) -> bool:
         """Check if rendering is required by the app."""