fix(checkbox, toggle): uniform helper text style for ionic theme (#30893)

Issue number: resolves #

---------

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## What is the current behavior?
Helper and Error text style it's not uniform between elements.

## What is the new behavior?
* Changed the typography for `.checkbox-bottom` and `.toggle-bottom` to
use `globals.$ion-body-sm-medium` for a more consistent appearance with
other components.
[[1]](diffhunk://#diff-796ffc72b6171910c25d5aad085bc245095c38f104d55e253e06282702205066L116-R116)
[[2]](diffhunk://#diff-ad6128c5d08f42a970eab3a8c7081eaad590bd4ebbcd19ec4e6110a6f7977040L59-R70)
* Updated the color of `.input-bottom .helper-text` and `.input-bottom
.counter` to use `globals.$ion-text-subtlest` instead of
`globals.$ion-primitives-neutral-800`, and `.input-bottom .error-text`
to use `globals.$ion-text-danger`.
* Standardized `.textarea-bottom .error-text` to use
`globals.$ion-text-danger` and reordered the CSS for clarity, while
`.textarea-bottom .helper-text` and `.textarea-bottom .counter` use
`globals.$ion-text-subtlest`.
* Updated `.toggle-bottom .error-text` to use `globals.$ion-text-danger`
and `.toggle-bottom .helper-text` to use `globals.$ion-text-subtlest`
for improved semantic clarity and consistency.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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---------

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

core/src/components/checkbox/checkbox.ionic.scss

@@ -113,7 +113,7 @@ input {
 // ----------------------------------------------------------------
 
 .checkbox-bottom {
-  @include globals.typography(globals.$ion-body-md-regular);
+  @include globals.typography(globals.$ion-body-sm-medium);
 }
 
 .checkbox-bottom .error-text {

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

@@ -266,15 +266,15 @@
   @include globals.typography(globals.$ion-body-sm-medium);
 }
 
-.input-bottom .helper-text,
-.input-bottom .counter {
-  color: globals.$ion-primitives-neutral-800;
-}
-
 .input-bottom .error-text {
   color: globals.$ion-text-danger;
 }
 
+.input-bottom .helper-text,
+.input-bottom .counter {
+  color: globals.$ion-text-subtlest;
+}
+
 :host(.has-focus.ion-valid) .helper-text {
   color: var(--highlight-color-valid);
 }

core/src/components/textarea/textarea.ionic.scss

@@ -141,15 +141,15 @@ ion-icon {
   @include globals.typography(globals.$ion-body-sm-medium);
 }
 
+.textarea-bottom .error-text {
+  color: globals.$ion-text-danger;
+}
+
 .textarea-bottom .helper-text,
 .textarea-bottom .counter {
   color: globals.$ion-text-subtlest;
 }
 
-.textarea-bottom .error-text {
-  color: globals.$ion-text-danger;
-}
-
 :host(.has-focus.ion-valid) .helper-text {
   color: var(--highlight-color-valid);
 }

core/src/components/toggle/toggle.ionic.scss

@@ -56,18 +56,18 @@
 // ----------------------------------------------------------------
 
 .toggle-bottom {
-  @include globals.typography(globals.$ion-body-md-regular);
+  @include globals.typography(globals.$ion-body-sm-medium);
 }
 
 // Toggle Hint Text
 // ----------------------------------------------------------------
 
 .toggle-bottom .error-text {
-  color: globals.$ion-semantics-danger-900;
+  color: globals.$ion-text-danger;
 }
 
 .toggle-bottom .helper-text {
-  color: globals.$ion-primitives-neutral-900;
+  color: globals.$ion-text-subtlest;
 }
 
 // Toggle Native Wrapper: Focused