refactor: Improve noxfile.py

- Installed `virtualenv` and `cmake` before other dependencies.
- Installed all and dev dependencies together using a single `pip` command to avoid redundant wheel building.
- Corrected sys.platform to maintain consistency in the code

Signed-off-by: Akhilender <[email protected]>

noxfile.py

@@ -118,24 +118,13 @@ def run_scripts(session):
 def set_dev(session):
     """Install PyBaMM in editable mode."""
     set_environment_variables(PYBAMM_ENV, session=session)
-    envbindir = session.bin
-    session.install("virtualenv")
+    session.install("virtualenv","cmake")
     session.run("virtualenv", os.fsdecode(VENV_DIR), silent=True)
     python = os.fsdecode(VENV_DIR.joinpath("bin/python"))
-    session.run(python, "-m", "pip", "install", "-e", ".[all]", silent=False)
-    session.install("cmake", silent=False)
-    session.install("-e", ".[dev]", external=True)
-    if session.platform.startswith("macos") or session.platform.startswith("linux"):
+    session.run(python, "-m", "pip", "install", "-e", ".[all,dev]", silent=False)
+    if sys.platform == "linux" or sys.platform == "macos":
         session.run(python, "-m", "pip", "install", ".[jax,odes]", silent=False)
-    if sys.platform == "linux" or sys.platform == "darwin":
-        session.run(
-            "echo",
-            "export",
-            f"LD_LIBRARY_PATH={PYBAMM_ENV['LD_LIBRARY_PATH']}",
-            ">>",
-            f"{envbindir}/activate",
-            external=True,  # silence warning about echo being an external command
-        )
+
 
 
 @nox.session(name="tests")