refactor(input-otp): update according to design (#30765)

Issue number: internal

---------

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## What is the current behavior?
The input-otp component does not currently match our UX designs for the
ionic theme.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->
- Changed shape design tokens;
- Changed background to use correct design token.

## 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. -->

core/src/components/input-otp/input-otp.common.scss

@@ -129,13 +129,6 @@
   background: var(--separator-color);
 }
 
-// Fills
-// --------------------------------------------------
-
-:host(.input-otp-fill-outline) {
-  --background: none;
-}
-
 // States
 // --------------------------------------------------
 

core/src/components/input-otp/input-otp.ionic.scss

@@ -68,20 +68,24 @@
 // --------------------------------------------------
 
 :host(.input-otp-shape-round) {
-  --border-radius: #{globals.$ion-border-radius-400};
+  --border-radius: #{globals.$ion-round-xl};
 }
 
 :host(.input-otp-shape-soft) {
-  --border-radius: #{globals.$ion-border-radius-200};
+  --border-radius: #{globals.$ion-soft-xl};
 }
 
 :host(.input-otp-shape-rectangular) {
-  --border-radius: #{globals.$ion-border-radius-0};
+  --border-radius: #{globals.$ion-rectangular-xl};
 }
 
 // Fills
 // --------------------------------------------------
 
+:host(.input-otp-fill-outline) {
+  --background: #{globals.$ion-bg-input-default};
+}
+
 :host(.input-otp-fill-solid) {
   --border-color: #{globals.$ion-bg-input-bold-default};
   --background: #{globals.$ion-bg-input-bold-default};