Always generate webhook secrets by default

[rolodato]

Is your feature request related to a problem? Please describe.

When creating a webhook, the "Secret" field is optional and blank by default:

In most cases, this will be fine. However, a more secure default would be to generate a random secret directly from the browser. There's really no reason to ever use unsigned webhooks - if users don't care about the signature, they can choose to not verify it.

Describe the solution you'd like.

Generate random webhook secrets directly when configuring them. Add an option to regenerate a secret if it needs to be changed.

Potentially, do not allow blank webhook secrets entirely.

Describe alternatives you've considered

🤷

Additional context

No response