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 <hi@ionicframework.com>

core/src/components/item/test/groups/index.html

@@ -20,7 +20,7 @@
         <ion-toolbar>
           <ion-title>Item Groups</ion-title>
           <ion-buttons slot="primary">
-            <ion-button onclick="reload()"> Reload </ion-button>
+            <ion-button onclick="reload()">Reload</ion-button>
           </ion-buttons>
         </ion-toolbar>
       </ion-header>

core/src/components/item/test/inputs/index.html

@@ -80,9 +80,7 @@
             </ion-item>
           </ion-list>
 
-          <ion-button class="ion-padding-horizontal ion-margin-top" id="submit" type="submit" expand="block"
-            >Submit
-          </ion-button>
+          <button id="submit" type="submit" class="expand">Submit</button>
           <p id="form-result"></p>
         </form>
       </ion-content>