feat(input): remove size property in favor of CSS styling (#28903)

Issue number: Internal

---------

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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

The `ion-input` component currently specifies a `size` attribute to
align with the HTML `input` implementation. However, Ionic's custom
appearance for MD and iOS is not compatible and should not be used with
the `size` attribute:
https://github.com/ionic-team/ionic-framework/issues/27945#issuecomment-1669702274.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- The `size` property has been removed from `ion-input`.

## Does this introduce a breaking change?

- [x] Yes
- [ ] No

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The `size` attribute has been removed from `ion-input`. As it was not
compatible before, this is likely to have a minimal impact to
developers. If your application is using the `size` attribute, replace
the usage with CSS styling to control the width of the `ion-input`.


## Other information

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screenshots of how the component looks before and after the change. -->

core/src/components/input/input.tsx

@@ -281,9 +281,6 @@ export class Input implements ComponentInterface {
    */
   @Prop() step?: string;
 
-  // FW-4914 Remove this property in Ionic 8
-  @Prop() size?: number;
-
   /**
    * The type of control to display. The default type is text.
    */
@@ -806,7 +803,6 @@ export class Input implements ComponentInterface {
               required={this.required}
               spellcheck={this.spellcheck}
               step={this.step}
-              size={this.size}
               type={this.type}
               value={value}
               onInput={this.onInput}
@@ -915,7 +911,6 @@ Developers can dismiss this warning by removing their usage of the "legacy" prop
           required={this.required}
           spellcheck={this.spellcheck}
           step={this.step}
-          size={this.size}
           type={this.type}
           value={value}
           onInput={this.onInput}