globally remove link tap highlighting (#11872)

### WHY are these changes introduced?

When tapping links with an iOS device, it highlights the element with a
grey background. This is undesirable and we should rely on locally
defined styles for tappable elements. [Slack
thread](https://shopify.slack.com/archives/C052FLLS8V6/p1711024818880199)

Example:
https://share.descript.com/view/ognFPIjLAzV

### WHAT is this pull request doing?

The proposed solution solution is to set
[-webkit-tap-highlight-color](https://developer.mozilla.org/en-US/docs/Web/CSS/-webkit-tap-highlight-color)
to `transparent` globally. This will disable the appearance of tap
highlighting.

### How to 🎩

🖥 [Local development
instructions](https://github.com/Shopify/polaris/blob/main/README.md#install-dependencies-and-build-workspaces)
🗒 [General tophatting
guidelines](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md)
📄 [Changelog
guidelines](https://github.com/Shopify/polaris/blob/main/.github/CONTRIBUTING.md#changelog)


[Spin](https://admin.web.webkit-tap-highlight-color.matt-kubej.us.spin.dev/store/shop1)

Open the spin instance above via a Simulated iOS device or a real device
via BrowserStack, then navigate into the settings of Admin, such as
Markets, and validate the grey tap highlighting as seen in the descript
video is no longer present.

### 🎩 checklist

- [x] Tested a
[snapshot](https://github.com/Shopify/polaris/blob/main/documentation/Releasing.md#-snapshot-releases)
- [x] Tested on
[mobile](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md#cross-browser-testing)
- [x] Tested on [multiple
browsers](https://help.shopify.com/en/manual/shopify-admin/supported-browsers)
- [x] Tested for
[accessibility](https://github.com/Shopify/polaris/blob/main/documentation/Accessibility%20testing.md)
- [x] Updated the component's `README.md` with documentation changes
- [x] [Tophatted
documentation](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting%20documentation.md)
changes in the style guide

.changeset/clever-lobsters-watch.md

@@ -0,0 +1,5 @@
+---
+'@shopify/polaris': patch
+---
+
+globally remove link tap highlighting

polaris-react/src/components/AppProvider/global.css

@@ -59,6 +59,7 @@ body {
   font-feature-settings: 'calt' 0;
   letter-spacing: initial;
   color: var(--p-color-text);
+  -webkit-tap-highlight-color: transparent;
 }
 
 html,