Closes elastic#205805

This PR extracts the share export functionality into a standalone
triggered UI action, and builds mostly off of the work that's been done
in elastic#211665 as such any share
integration type that's registered under the groupId `export` will show
up within the afore mentioned standalone export type.

Registering a new export type would happen like so;

```js
share.registerShareIntegration({
	groupId: 'export',
	...
	config: () => ({
		...
	}),
	prerequisiteCheck({ license, capabilities, objectType }) {
		// The prerequisiteCheck callback will get passed the license, app capabilities and the objectType
		// of the current caller, this can then be used to determine if this integration should be available,
		// returning false in here disables the integration,
	}
})
```

*P.S.* This registration can also be scoped to a particular object type
(i.e. lens, dashboard etc.) if said integration is intended to only be
available for only a particular object type.

<img width="768" alt="Screenshot 2025-04-24 at 10 53 25"
src="https://github.com/user-attachments/assets/31966ded-b1f7-417e-840e-4596b310d6bc"
/>

<img width="1720" alt="Screenshot 2025-04-25 at 09 04 50"
src="https://github.com/user-attachments/assets/8b675974-9a4b-4dcc-9aca-77cea5a25654"
/>

<img width="640" alt="Screenshot 2025-04-24 at 10 53 40"
src="https://github.com/user-attachments/assets/d16da148-3c25-4a58-a847-d4d5a3736106"
/>

button visible)_
<img width="1728" alt="Screenshot 2025-05-02 at 13 11 21"
src="https://github.com/user-attachments/assets/e47426fb-db5b-4c2a-bee5-557fefbb40ec"
/>

<img width="626" alt="Screenshot 2025-04-04 at 20 18 50"
src="https://github.com/user-attachments/assets/f4bdd2a3-2527-4334-b253-7686e4131d87"
/>
<img width="1728" alt="Screenshot 2025-05-02 at 13 11 43"
src="https://github.com/user-attachments/assets/9a6e7fa2-260d-4b68-a1ae-61c499849fb8"
/>

- Pull this PR and run it locally, or test in the provision environment
linked to this PR.
- Navigate to the dashboard, discover, and visualize app. The nav menu
should display icon buttons for sharing and export.
- Clicking the "Share" icon (up arrow) opens the familiar share modal
without export. The "Export" icon (down arrow) opens a new popover with
available options.
- Export Functionality Test;
- Single Export Option: When there's only one export option, the flyout
opens automatically.
- Disabled Reporting Features: Create a new role with reporting
subPrivileges and test it by creating a user assigned to that role. Log
in as the user, and the export popover should reflect the limited
reporting features.
- In the case where the current user has no registered integrations
available to them, the export functionality will not be displayed

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---------

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
(cherry picked from commit a887cd6)