fix: activate venv before uv pip install

uv pip needs the venv to be activated (VIRTUAL_ENV set) to find it.
Setting VIRTUAL_ENV and PATH ensures uv can locate the venv.

ct/plane.sh

@@ -67,6 +67,8 @@ function update_script() {
 
     msg_info "Updating Python Dependencies"
     cd /opt/plane/apps/api
+    export VIRTUAL_ENV=/opt/plane-venv
+    export PATH="/opt/plane-venv/bin:$PATH"
     $STD uv pip install --upgrade -r requirements/production.txt
     msg_ok "Updated Python Dependencies"