feat(progress-bar): add styling for the ionic theme (#30185)

Issue number: internal

---------

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## What is the current behavior?
ion-progress-bar does not currently have any custom styling for the
ionic theme.

## What is the new behavior?
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this PR. -->
According to the design, the following styling changes were made:
- Added a new shape prop which controls the shape of the progress bar
- Changed the color of the unfilled part of the progress bar and the bar
height to design token values
- Adding a new testing page and screenshot tests

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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## Other information

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

packages/angular/standalone/src/directives/proxies.ts

@@ -1593,14 +1593,14 @@ Shorthand for ionPickerDidDismiss.
 
 @ProxyCmp({
   defineCustomElementFn: defineIonProgressBar,
-  inputs: ['buffer', 'color', 'mode', 'reversed', 'theme', 'type', 'value']
+  inputs: ['buffer', 'color', 'mode', 'reversed', 'shape', 'theme', 'type', 'value']
 })
 @Component({
   selector: 'ion-progress-bar',
   changeDetection: ChangeDetectionStrategy.OnPush,
   template: '<ng-content></ng-content>',
   // eslint-disable-next-line @angular-eslint/no-inputs-metadata-property
-  inputs: ['buffer', 'color', 'mode', 'reversed', 'theme', 'type', 'value'],
+  inputs: ['buffer', 'color', 'mode', 'reversed', 'shape', 'theme', 'type', 'value'],
   standalone: true
 })
 export class IonProgressBar {