fix(angular): type resolution with strict templates

[sean-perkins]

Pull request checklist

Please check if your PR fulfills the following requirements:

• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been reviewed and added / updated if needed (for bug fixes / features)
  • Some docs updates need to be made in the ionic-docs repo, in a separate PR. See the contributing guide for details.
• [x] Build (npm run build) was run locally and any changes were pushed
• [x] Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• [x] Bugfix
• [ ] Feature
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] Documentation content changes
• [ ] Other (please describe):

What is the current behavior?

Angular Language Service will complain when using output bindings in HTML.

For example:

<ion-reorder (ionItemReorder)="doReorder($event)">

The type of $event is event: Event, which is incompatible with the expected signature: CustomEvent<ItemReorderEventDetail>.

This causes both type/build errors.

Issue URL: #24245

What is the new behavior?

• Deprecates the existing custom event types in preference of the Stencil generated types
• Uses the updated dev-build of @stencil/angular-output-targets, which includes changes to take advantage of the new custom event types and workaround Angular behavior with Angular Language Service

Does this introduce a breaking change?

• [ ] Yes
• [x] No

Other information

Dev-build: 6.1.11-dev.11655500065.1d345d4c

We should wait several release cycles before merging this fix in, due to the nature of the change. Possibly into 6.2.0.