test(toast): migrate to generators (#27388)

Issue number: N/A

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## What is the current behavior?
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Toast tests are using legacy syntax.

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

- Toast tests are using generator syntax.


https://github.com/ionic-team/ionic-framework/pull/27388/commits/6cfddff994317221b21498a08dca086882a1093b

- htmlAttributes and duration config tests were converted to spec tests.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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## Other information

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