feat(cloud): don't apply length and pattern validation to FEEL

[philippfromme]

Try out via npm start.

Related to https://github.com/camunda/camunda-modeler/issues/4140

Proposed Changes

### Checklist To ensure you provided everything we need to look at your PR: * [x] **Brief textual description** of the changes present * [x] **Visual demo** attached * [x] **Steps to try out** present, i.e. [using the `@bpmn-io/sr` tool](https://github.com/bpmn-io/sr) * [x] Related issue linked via `Closes {LINK_TO_ISSUE}` or `Related to {LINK_TO_ISSUE}`

[philippfromme]

One UX issue I found with this is that the error message stays until there is an actual value. There is some internal state of the FEEL entry that decides whether it's FEEL and doesn't actually commit the initial = until you enter something else like =foo. That internal state is not accessable outside of the FEEL entry. @marstamm Any idea if we can do something about that?

[marstamm]

As we have validation only when a value is persisted in other places as well (e.g. when you are still typing), I think this is fine for now. In these cases, it is basically "Should not be empty" but with another error message. I don't think this will be to confusing for the user, as the message disappears once an expression is present

[philippfromme]

@marstamm In that case it's ready for review.

[nikku]

Published as https://github.com/bpmn-io/bpmn-js-element-templates/releases/tag/v2.2.0.