fix(labels): prevent clicking a label from triggering onClick twice on several components (#30384)

Issue number: resolves #30165

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## What is the current behavior?
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Currently, several components will trigger their `onClick` twice if you
click on their labels.

## What is the new behavior?
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this PR. -->
After this fix, the affected components will only trigger `onClick` once
per click of their labels or click directly on the element.

## 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. -->

The affected components are:
- Checkbox
- Select
- Textarea
- Toggle
- Input

I also tested radio and range but could not reproduce the issue for
them.

Note that two of the components, checkbox and toggle, had to have
special implementations for both their test and fix because of how the
host component acts as the component for accessibility purposes.

Current dev build: `8.5.7-dev.11746044124.147aab6c`

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Co-authored-by: Maria Hutt <thetaPC@users.noreply.github.com>
Co-authored-by: Brandy Smith <brandyscarney@users.noreply.github.com>

core/src/components/select/select.tsx

@@ -911,6 +911,18 @@ export class Select implements ComponentInterface {
     return this.label !== undefined || this.labelSlot !== null;
   }
 
+  /**
+   * Stops propagation when the label is clicked,
+   * otherwise, two clicks will be triggered.
+   */
+  private onLabelClick = (ev: MouseEvent) => {
+    // Only stop propagation if the click was directly on the label
+    // and not on the input or other child elements
+    if (ev.target === ev.currentTarget) {
+      ev.stopPropagation();
+    }
+  };
+
   /**
    * Renders the border container
    * when fill="outline".
@@ -1173,7 +1185,7 @@ export class Select implements ComponentInterface {
           [`select-label-placement-${labelPlacement}`]: true,
         })}
       >
-        <label class="select-wrapper" id="select-label">
+        <label class="select-wrapper" id="select-label" onClick={this.onLabelClick}>
           {this.renderLabelContainer()}
           <div class="select-wrapper-inner">
             <slot name="start"></slot>