Updated Polyscript with its workers feature (#2104)

* Updated Polyscript with its workers feature
* Worked around the inconsistent behavior between Pyodide and MicroPython
* Fixed Pyodide greedy access to undesired Proxy fields

pyscript.core/test/workers/worker.py

@@ -0,0 +1,7 @@
+def micropython_version():
+    import sys
+
+    return sys.version
+
+
+__export__ = ["micropython_version"]