test(many): replace ionic buttons in e2e tests with native html buttons (#29422)

Issue number: internal

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## What is the current behavior?
The `ion-button` component is used in several tests to navigate or show
overlays. This causes screenshot diffs in unrelated tests any time the
UI of the `ion-button` is updated.

## What is the new behavior?
Removes the `ion-button` elements from unrelated tests. 

Did not remove the `ion-button`s from the following tests:
- All `ion-button`s in an `ion-buttons` component
- An `ion-button` inside of a menu
- breadcrumbs/test/basic (uses a clear button in a list header, needs to
be moved)
- input/test/slot
- item/test/buttons
- item/test/colors
- item/test/dividers
- item/test/inputs
- item/test/media
- list-header/test/basic
- ripple-effect/test/basic
- router/test/basic
- router/test/guards
- router-outlet/test/basic
- select/test/slot
- textarea/test/slot

Updates the icon/basic test to use the right icon names by comparing
against the v3 names: https://ionicframework.com/docs/v3/ionicons/

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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Co-authored-by: ionitron <[email protected]>

Author: brandyscarney

core/scripts/testing/styles.css

@@ -19,14 +19,14 @@
     <main class="ion-padding">
       <h1>Action Sheet - A11y</h1>
 
-      <ion-button id="bothHeaders" onclick="presentBothHeaders()">Both Headers</ion-button>
-      <ion-button id="subHeaderOnly" onclick="presentSubHeaderOnly()">Subheader Only</ion-button>
-      <ion-button id="noHeaders" onclick="presentNoHeaders()">No Headers</ion-button>
-      <ion-button id="customAria" onclick="presentCustomAria()">Custom Aria</ion-button>
-      <ion-button id="ariaLabelButton" onclick="presentAriaLabelButton()">Aria Label Button</ion-button>
-      <ion-button id="ariaLabelCancelButton" onclick="presentAriaLabelCancelButton()"
-        >Aria Label Cancel Button</ion-button
-      >
+      <button class="expand" id="bothHeaders" onclick="presentBothHeaders()">Both Headers</button>
+      <button class="expand" id="subHeaderOnly" onclick="presentSubHeaderOnly()">Subheader Only</button>
+      <button class="expand" id="noHeaders" onclick="presentNoHeaders()">No Headers</button>
+      <button class="expand" id="customAria" onclick="presentCustomAria()">Custom Aria</button>
+      <button class="expand" id="ariaLabelButton" onclick="presentAriaLabelButton()">Aria Label Button</button>
+      <button class="expand" id="ariaLabelCancelButton" onclick="presentAriaLabelCancelButton()">
+        Aria Label Cancel Button
+      </button>
     </main>
 
     <script>