fix: add URI validation to webhook connectors

[ev-codes]

Description

Check that webhook ID contains only valid URI characters as outlined in RFC 3986 for the following:

• Webhook Start Event Connector
• Webhook Intermediate Event Connector

Before:

After:

Webhook ID's form part of a URL. As such, the ID needs to be a valid URI in order to prevent obviously malformed URL's. See #1238 for more details.

More Details

Allowing "/"

There was discussion in #1238 to disallow the forward slash "/" as this could be misconstrued as a path delimiter.

I personally feel we should still allow "/" because it is still syntactically correct. I don't want to enforce semantics, as it's possible there are some use cases where a Webhook ID could have a "/".

Test Cases

Checked the following for all connectors in Desktop Modeller:

Should show error message:

• "Start event"
• "Start event€"
• " Start event "

Should not show error message:

• "12345"
• "abcde"
• "_start_event_"
• "%20start%20event%20"

Next Steps

• Other generic webhook connectors (e.g., webhook-connector-boundary)
• 3rd party service webhook connectors (e.g., Twilio)

I wanted to wait to get feedback on my first implementation before expanding this approach to many other connectors.

Related issues

#1238

[ev-codes]

Closing for now while we pause work on #1238. See issue for more details.