[Tooltip] Change content type to allow React.Node

[YannCedric]

WHY are these changes introduced?

Fixes #3541

WHAT is this pull request doing?

Change content prop's type to not only accept string, but any React.Node.

How to 🎩

🖥 Local development instructions
🗒 General tophatting guidelines
📄 Changelog guidelines

Copy-paste this code in playground/Playground.tsx:

import React from 'react';
import {Page} from '../src';

export function Playground() {
  return (
    <Page title="Playground">
      {/* Add the code you want to test in here */}
    </Page>
  );
}

🎩 checklist

• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility
• Updated the component's README.md with documentation changes
• Tophatted documentation changes in the style guide
• For visual design changes, pinged one of @ HYPD, @ mirualves, @ sarahill, or @ ry5n to update the Polaris UI kit

[ghost]

👋 Thanks for opening your first pull request. A contributor should give feedback soon. If you haven’t already, please check out the contributing guidelines.

[github-actions]

🟢 This pull request modifies 2 files and might impact 3 other files.

Details:

All files potentially affected (total: 3)

• /src/components/Pagination/Pagination.tsx
• /src/components/Page/components/Header/Header.tsx
• /src/components/Page/Page.tsx

📄 UNRELEASED.md (total: 0)

Files potentially affected (total: 0)

🧩 src/components/Tooltip/Tooltip.tsx (total: 3)

Files potentially affected (total: 3)

• /src/components/Pagination/Pagination.tsx
• /src/components/Page/components/Header/Header.tsx
• /src/components/Page/Page.tsx

[BPScott]

Thanks!

Merge whenever you're ready.

[ghost]

🎉 Thanks for your contribution to Polaris React!