openapi/python_examples: Update examples for add/remove subscriptions.
openapi/python_examples: Update examples for add/remove subscriptions.

This updates the examples to use user ids to add or remove subscriptions
from a stream.

synicalsyntax/zulip,rht/zulip,shubhamdhama/zulip,synicalsyntax/zulip,showell/zulip,shubhamdhama/zulip,showell/zulip,brainwane/zulip,showell/zulip,synicalsyntax/zulip,zulip/zulip,brainwane/zulip,synicalsyntax/zulip,andersk/zulip,timabbott/zulip,synicalsyntax/zulip,hackerkid/zulip,andersk/zulip,rht/zulip,zulip/zulip,timabbott/zulip,showell/zulip,punchagan/zulip,brainwane/zulip,brainwane/zulip,synicalsyntax/zulip,eeshangarg/zulip,andersk/zulip,hackerkid/zulip,timabbott/zulip,rht/zulip,kou/zulip,synicalsyntax/zulip,hackerkid/zulip,shubhamdhama/zulip,eeshangarg/zulip,zulip/zulip,shubhamdhama/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,punchagan/zulip,hackerkid/zulip,brainwane/zulip,timabbott/zulip,shubhamdhama/zulip,hackerkid/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,rht/zulip,zulip/zulip,zulip/zulip,shubhamdhama/zulip,kou/zulip,rht/zulip,showell/zulip,showell/zulip,andersk/zulip,punchagan/zulip,timabbott/zulip,timabbott/zulip,zulip/zulip,punchagan/zulip,kou/zulip,andersk/zulip,rht/zulip,punchagan/zulip,hackerkid/zulip,punchagan/zulip,zulip/zulip,punchagan/zulip,timabbott/zulip,shubhamdhama/zulip,brainwane/zulip,hackerkid/zulip,rht/zulip,eeshangarg/zulip,kou/zulip,showell/zulip,brainwane/zulip