Add back jupyter PWD env var for agentskills

[xingyaoww]

We introduce JUPYTER_PWD in https://github.com/OpenDevin/OpenDevin/pull/2105/files#diff-fbc8351b325a35a525f30e58eae651dbd50b3692963c81b989bee4dac617511c, so that every create_file, open_file command from agentskills is aware of the (bash's) current working directory.

It got accidentally removed in this commit: 78e003c

Adding it back now.

Example, when cd into a folder aaa, the new create_file command should create file inside aaa, instead of `/workspace':

[xingyaoww]

pls Hold-off the merging for a bit - I'm trying to add a unit test to catch this

EDIT: ready now! waiting for workflow to finish.