Decrease python test concurrency to 1

Author: jakubno

.changeset/friendly-brooms-cry.md

@@ -4,4 +4,4 @@ markers =
     skip_debug: skip test if E2B_DEBUG is set.
 asyncio_mode=auto
 
-addopts = "--import-mode=importlib" "--numprocesses=2"
+addopts = "--import-mode=importlib" "--numprocesses=1"