Expose write access to workers' scripts "create tail" endpoint as a separate token permission

[captain-kark]

https://github.com/cloudflare/cloudflare-rs/blob/bb294900b8a46ba69cf2aa23dd5c449ef45d01d3/cloudflare/src/endpoints/workers/create_tail.rs#L6

Originally filed as cloudflare/wrangler#1563 which has more context.

It would be nice to grant permission to "read" logs from workers independently of granting permission to write arbitrary workers scripts. It would be great if this could be brought in under account permission 1a71c399035b4950a1bd1466bbe4f420: Workers Scripts Read.