Remove default value for epochs

[Tzal3x]

Description

While using devnet we would not specify the number of epochs and the walrus blobs would not get deleted.

Now with testnet we have to specify a number of epochs in publish command, otherwise it will default to 1.

Some users might not expect this kind of behaviour, so we should shed some light to it with a warning like "WARN: no number of epochs specified, defaulting to 1".

Having a default value to the epochs param, can result in deletion of sites while users might not expect this.

Component

site-builder

Code of Conduct

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[giac-mysten]

I think we should just have no default

[Tzal3x]

Ok then, sounds good.