style(segment-button): add and update color to slotted children for improved styling consistency (#30905)

Issue number: resolves internal

---------

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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->
- Previously in iOS, when using something different than the `ion-label`
to add a text inside the `segment-button`, the default color attributed
to it was blue.
<img width="357" height="103" alt="image"
src="https://github.com/user-attachments/assets/2196e548-f0b7-4e7f-b093-e58c88b2a6cb"
/>

- In Android, the expected color is not attributed either, but it
defaults to black instead of blue.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->
- Now, all the slotted elements will respect the color defined by the
`color` CSS variable.

## Does this introduce a breaking change?
- [ ] Yes
- [x] No

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  2. Update the BREAKING.md file with the breaking change.
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## Other information

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

core/src/components/segment-button/segment-button.ionic.scss

@@ -10,7 +10,7 @@
    */
   --background: none;
   --background-checked: var(--background);
-  --color: #{globals.$ion-primitives-neutral-1000};
+  --color: #{globals.$ion-primitives-neutral-1200};
   --color-checked: #{globals.$ion-semantics-primary-base};
   --color-disabled: #{globals.$ion-primitives-neutral-500};
   --border-width: #{globals.$ion-border-size-025};
@@ -44,13 +44,15 @@
   gap: globals.$ion-space-100;
 }
 
+::slotted(*) {
+  color: var(--color);
+}
+
 // Segment Button Label
 // --------------------------------------------------
 
 ::slotted(ion-label) {
   @include globals.typography(globals.$ion-body-action-sm);
-
-  color: var(--color);
 }
 
 // Segment Button Icon
@@ -59,8 +61,6 @@
 ::slotted(ion-icon) {
   width: globals.$ion-scale-600;
   height: globals.$ion-scale-600;
-
-  color: var(--color);
 }
 
 // Segment Button: Checked