chore(ci): add workflow for testing ionicons dev build (#28345)

Issue number: N/A

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## What is the current behavior?
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Testing Ionicons in Ionic is currently difficult. Developers need to a)
create a dev build of Ionicons, b) create a branch in Ionic, c) install
the dev build in Ionic core, d) push the branch, and e) create a draft
PR to watch the CI process run.

## What is the new behavior?
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this PR. -->

- Introduces a workflow dispatch option for our CI process. This allows
developers to run the CI process for any branch without creating PR.
- I also added an optional input so devs can specify the ionicons
version if they want to pass a special version.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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and migration path for existing applications below. -->


## Other information

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