>[!IMPORTANT]
This PR introduces the Borealis enabled EUI package to `8.x`.
The intention is to support new features being developed that need to
live in `main` as well as `8.x`.


>[!IMPORTANT]
All `8.x` versions should continue to use the current Amsterdam theme.
To ensure this even with upcoming changes to the default theme for EUI,
we're adding `euiThemeAmsterdam` on `EuiProvider` usages manually.

## Description

This PR introduces all previous Borealis related PR changes but excludes
the specific changes to support `@elastic/eui-theme-borealis` as only
Amsterdam is supported as theme in `8.x`.

Previous PRs

- #199993
- #201049
- #202073

---

`v97.3.1`⏩`v98.2.1-borealis.1`

_[Questions? Please see our Kibana upgrade
FAQ.](https://github.com/elastic/eui/blob/main/wiki/eui-team-processes/upgrading-kibana.md#faq-for-kibana-teams)_

---

# `@elastic/eui`

## [`v98.2.1`](https://github.com/elastic/eui/releases/v98.2.1)

- Updated the EUI theme color values to use a full 6 char hex code
format ([#8244](elastic/eui#8244))

## [`v98.2.0`](https://github.com/elastic/eui/releases/v98.2.0)

- Added two new icons: `contrast` and `contrastHigh`
([#8216](elastic/eui#8216))
- Updated `EuiDataGrid` content to have a transparent background.
([#8220](elastic/eui#8220))

**Accessibility**

- When the tooltips components (`EuiTooltip`, `EuiIconTip`) are used
inside components that handle the Escape key (like `EuiFlyout` or
`EuiModal`), pressing the Escape key will now only close the tooltip and
not the entire wrapping component.
([#8140](elastic/eui#8140))
- Improved the accessibility of `EuiCodeBlock`s by
([#8195](elastic/eui#8195))
  - adding screen reader only labels
  - adding `role="dialog"` on in fullscreen mode
  - ensuring focus is returned on closing fullscreen mode
  
# Borealis updates
  
- [Visual Refresh] Update color token mappings
([#8211](elastic/eui#8211))
- [Visual Refresh] Introduce shared popover arrow styles to Borealis
([#8212](elastic/eui#8212))
- [Visual Refresh] Add forms.maxWidth token
([#8221](elastic/eui#8221))
- [Visual Refresh] Set darker shade for subdued text
([#8224](elastic/eui#8224))
- [Visual Refresh] Remove support for accentSecondary badges
([#8224](elastic/eui#8227))
- [Visual Refresh] Add severity vis colors
([#8247](elastic/eui#8247))

---

# `@elastic/eui`

## [`v98.1.0`](https://github.com/elastic/eui/releases/v98.1.0)

- Updated `EuiBetaBadge` with a new `warning` color variant
([#8177](elastic/eui#8177))

**Accessibility**

- Ensures `autoFocus` on `EuiSelectableList` triggers initial focus
([#8091](elastic/eui#8091))
- Improved the accessibility of `EuiSearchBarFilters` by:
([#8091](elastic/eui#8091))
  - adding a more descriptive `aria-label` to selection filter buttons
- ensuring the selection listbox is initially focused when opening a
selection popover
- Improved the accessibility experience of tabs (EuiTab, EuiTabs): tab
group is a tab stop and tabs can be traversed with arrow keys.
([#8116](elastic/eui#8116))
- Updated `EuiCodeBlock` with a new `copyAriaLabel` prop, which allows
setting a custom screen reader label on the copy button.
([#8176](elastic/eui#8176))

**CSS-in-JS conversions**

- Removed the following global Sass variables:
([#8169](elastic/eui#8169))
  - `$euiButtonMinWidth`
  - `$euiDatePickerCalendarWidth`
- Removed the following Sass animations:
([#8169](elastic/eui#8169))
  - `euiAnimFadeIn`
  - `euiGrow`
  - `focusRingAnimate`
  - `focusRingAnimateLarge`
  - `euiButtonActive`
- Removed the following Sass mixins:
([#8169](elastic/eui#8169))
  - `euiFullHeight`
  - `euiSlightShadowHover`
  - `datePickerArrow`

# Borealis updates

- [Visual Refresh] Fix euiColorFullShade Sass variable mapping
(elastic/eui#8178)

---

# `@elastic/eui`

## [`v98.0.0`](https://github.com/elastic/eui/releases/v98.0.0)

**Bug fixes**

- Fixed an `EuiDataGrid` bug where column actions where not clickable
when `EuiDataGrid` with `columnVisibility.canDragAndDropColumns` was
used inside a modal ([#8135](elastic/eui#8135))

**Breaking changes**

- Removed `EuiFormRow`'s deprecated `columnCompressedSwitch` display
prop. Use `columnCompressed` instead
([#8113](elastic/eui#8113))

# Borealis updates

**Bug fixes**

- Fixed computed border token mapping
(elastic/eui#8170)