refactor(select): remove legacy property and support for legacy syntax (#29024)

Issue number: internal

---------

## What is the current behavior?

In Ionic Framework v7, we [simplified the select
syntax](https://ionic.io/blog/ionic-7-is-here#simplified-form-control-syntax)
so that it was no longer required to be placed inside of an `ion-item`.
We maintained backwards compatibility by adding a `legacy` property
which allowed it to continue to be styled properly when written in the
following way:

```html
<ion-item>
  <ion-label>Label</ion-label>
  <ion-select></ion-select>
</ion-item>
```

While this was supported in v7, console warnings were logged to notify
developers that they needed to update this syntax for the best
accessibility experience.

## What is the new behavior?

- Removes the `legacy` property and support for the legacy syntax.
Developers should follow the [migration
guide](https://ionicframework.com/docs/api/select#migrating-from-legacy-select-syntax)
in the select documentation to update their apps. The new syntax
requires a `label` or `aria-label` on `ion-select`:
    ```html
    <ion-item>
      <ion-select label="Label"></ion-select>
    </ion-item>
    ```
- Removes the legacy tests under under `select/test/legacy/` and all
related screenshots
- Removes the select usage from `item/test/disabled`,
`item/test/legacy/alignment`, and `item/test/legacy/disabled` and all
related screenshots if the test was removed

## Does this introduce a breaking change?

- [x] Yes
- [ ] No

1. Developers have had console warnings when using the legacy syntax
since the v7 release. The migration guide for the new select syntax is
outlined in the [Select
documentation](https://ionicframework.com/docs/api/select#migrating-from-legacy-select-syntax).
2. This change has been documented in the Breaking Changes document with
a link to the migration guide.

BREAKING CHANGE:

The `legacy` property and support for the legacy syntax, which involved
placing an `ion-select` inside of an `ion-item` with an `ion-label`,
have been removed from select. For more information on migrating from
the legacy select syntax, refer to the [Select
documentation](https://ionicframework.com/docs/api/select#migrating-from-legacy-select-syntax).

---------

Co-authored-by: ionitron <hi@ionicframework.com>

packages/angular/src/directives/proxies.ts

@@ -1975,7 +1975,7 @@ export declare interface IonSegmentButton extends Components.IonSegmentButton {}
 
 
 @ProxyCmp({
-  inputs: ['cancelText', 'color', 'compareWith', 'disabled', 'expandedIcon', 'fill', 'interface', 'interfaceOptions', 'justify', 'label', 'labelPlacement', 'legacy', 'mode', 'multiple', 'name', 'okText', 'placeholder', 'selectedText', 'shape', 'toggleIcon', 'value'],
+  inputs: ['cancelText', 'color', 'compareWith', 'disabled', 'expandedIcon', 'fill', 'interface', 'interfaceOptions', 'justify', 'label', 'labelPlacement', 'mode', 'multiple', 'name', 'okText', 'placeholder', 'selectedText', 'shape', 'toggleIcon', 'value'],
   methods: ['open']
 })
 @Component({
@@ -1983,7 +1983,7 @@ export declare interface IonSegmentButton extends Components.IonSegmentButton {}
   changeDetection: ChangeDetectionStrategy.OnPush,
   template: '<ng-content></ng-content>',
   // eslint-disable-next-line @angular-eslint/no-inputs-metadata-property
-  inputs: ['cancelText', 'color', 'compareWith', 'disabled', 'expandedIcon', 'fill', 'interface', 'interfaceOptions', 'justify', 'label', 'labelPlacement', 'legacy', 'mode', 'multiple', 'name', 'okText', 'placeholder', 'selectedText', 'shape', 'toggleIcon', 'value'],
+  inputs: ['cancelText', 'color', 'compareWith', 'disabled', 'expandedIcon', 'fill', 'interface', 'interfaceOptions', 'justify', 'label', 'labelPlacement', 'mode', 'multiple', 'name', 'okText', 'placeholder', 'selectedText', 'shape', 'toggleIcon', 'value'],
 })
 export class IonSelect {
   protected el: HTMLElement;