fix(angular): item styling when control has value

[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)
• Build (npm run build) was run locally and any changes were pushed
• 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:

• 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?

When a control, inside an ion-item is displayed within a modal; after opening, closing and re-opening the modal, the item-has-value class is not applied to the ion-item that wraps the control.

Issue URL: #23809

What is the new behavior?

• item-has-value is manually applied to the ion-item from the control value accessor, when applying other Ionic classes

Does this introduce a breaking change?

• Yes
• No

Other information

This PR does misc clean-up to deprecated substr and usage for add/remove classes.

Closing #24401 in favor of this PR.

[liamdebeasi]

Prior to merging, please provide the developers on #23809 with a dev build. I'd prefer to have some developer feedback before we ship this.

[liamdebeasi]

@sean-perkins We can probably merge this now. We've given developers time to test, and this new approach seems safer than the previous approach.