Fixes issues with consecutive python exe calls in isaaclab.bat (#598)

# Description

As reported in https://github.com/isaac-sim/IsaacLab/pull/3071, we have
some issues with the isaaclab.bat script when multiple calls to
`!python_exe!` are called, resulting in ` '!python_exe!' is not
recognized as an internal or external command` error messages. This fix
uses `call` command to expand `!python_exe!` to and correctly execute
the commands.

## Type of change

<!-- As you go through the list, delete the ones that are not
applicable. -->

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

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] 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

<!--
As you go through the checklist above, you can mark something as done by
putting an x character in it

For example,
- [x] I have done this task
- [ ] I have not done this task
-->

isaaclab.bat

@@ -516,7 +516,7 @@ if "%arg%"=="-i" (
             set "skip=1"
         )
     )
-    !python_exe! !allArgs!
+    call !python_exe! !allArgs!
     goto :end
 ) else if "%arg%"=="--python" (
     rem run the python provided by Isaac Sim
@@ -532,7 +532,7 @@ if "%arg%"=="-i" (
             set "skip=1"
         )
     )
-    !python_exe! !allArgs!
+    call !python_exe! !allArgs!
     goto :end
 ) else if "%arg%"=="-s" (
     rem run the simulator exe provided by isaacsim
@@ -577,11 +577,11 @@ if "%arg%"=="-i" (
         )
     )
     echo [INFO] Installing template dependencies...
-    !python_exe! -m pip install -q -r tools\template\requirements.txt
+    call !python_exe! -m pip install -q -r tools\template\requirements.txt
     echo.
     echo [INFO] Running template generator...
     echo.
-    !python_exe! tools\template\cli.py !allArgs!
+    call !python_exe! tools\template\cli.py !allArgs!
     goto :end
 ) else if "%arg%"=="--new" (
     rem run the template generator script
@@ -596,11 +596,11 @@ if "%arg%"=="-i" (
         )
     )
     echo [INFO] Installing template dependencies...
-    !python_exe! -m pip install -q -r tools\template\requirements.txt
+    call !python_exe! -m pip install -q -r tools\template\requirements.txt
     echo.
     echo [INFO] Running template generator...
     echo.
-    !python_exe! tools\template\cli.py !allArgs!
+    call !python_exe! tools\template\cli.py !allArgs!
     goto :end
 ) else if "%arg%"=="-t" (
     rem run the python provided by Isaac Sim
@@ -614,7 +614,7 @@ if "%arg%"=="-i" (
             set "skip=1"
         )
     )
-    !python_exe! -m pytest tools !allArgs!
+    call !python_exe! -m pytest tools !allArgs!
     goto :end
 ) else if "%arg%"=="--test" (
     rem run the python provided by Isaac Sim
@@ -628,7 +628,7 @@ if "%arg%"=="-i" (
             set "skip=1"
         )
     )
-    !python_exe! -m pytest tools !allArgs!
+    call !python_exe! -m pytest tools !allArgs!
     goto :end
 ) else if "%arg%"=="-v" (
     rem update the vscode settings