Slack Sink: iconEmoji, iconUrl, username are deprecated in camel

[manstis]

Please advise if you require Camel issues lodged for PRs vs third party tracking references.

The underlying Slack Component has deprecated a few parameters, namely iconEmoji, iconUrl and username.

This PR attempts to reflect the same in the corresponding Kamelet definition.

I'm uncertain if Kamelets even support the definition of deprecated parameters. Documentation isn't clear.

I'm even less clear, to be honest, whether the parameters in a Kamelet map to "Components Options" or "Query parameters" or both due to some clever name-based mapping in Camel. The three affected Kamelet parameters appear as parameters in the Kamelet but as "Query parameters" in the Component. The Kamelet parameter webhookUrl relates to a Component Option and Query parameter.

I suspect they only map to Component Options and hence the three "Query" parameters can be removed entirely and not just deprecated.

Advice welcome.

[oscerd]

Please don't use downstream JIRA. For the upstream there is no point in linking them. This is the upstream and we should focus on upstream only. I edited the text

[manstis]

Closing in lieu of #1330

Whatever solution is agreed will need to be enacted for this Slack Sink.