make delete a instance method

[howard-at-cb]

What changed? Why?

make python SDK's webhook deletion behave the same as node and ruby SDK, it will be a instance method without needing clients to enter a webhook ID.

 wh1 = next(gen1)
CDP API REQUEST: GET https://api.cdp.coinbase.com/platform/v1/webhooks?limit=100
CDP API RESPONSE: Status: 200, Data: b'{"data":[{"created_at":"2024-12-13T20:24:39.256Z","event_type":"smart_contract_event_activity","event_type_filter":{"contract_addresses":["0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48"]},"id":"675c980709b4be439a116ade","network_id":"ethereum-mainnet","notification_uri":"https://webhook.site/57cb34a7-51aa-4ba8-b0a5-b435bebf99a5","updated_at":"2024-12-16T21:47:29.07Z"}],"has_more":false}\n'
>>> wh1.delete_webhook()
CDP API REQUEST: DELETE https://api.cdp.coinbase.com/platform/v1/webhooks/675c980709b4be439a116ade
CDP API RESPONSE: Status: 200, Data: b''

Qualified Impact

[cb-heimdall]

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