feat(popover-container): align component with fusion designs

[edleeks87]

Proposed behaviour

Aligns with new PopoverContainer fusion designs
Uses next Button
Deprecates center alignment
Deprecates border radius prop
Adds translation key for default openButton.text()
Can be overridden by passing children directly as and when needed to open button render prop

Current behaviour

Not aligned with fusion
default open button is icon only and uses deprecated Button and IconButton

Checklist

• Commits follow our style guide
• Unit tests added or updated if required
• Playwright automation tests added or updated if required
• Storybook added or updated if required
• Translations added or updated (including creating or amending translation keys table in storybook) if required
• Typescript d.ts file added or updated if required

QA

• Tested in provided StackBlitz sandbox/Storybook
• Add new Playwright test coverage if required
• Carbon implementation matches Design System/designs
• UI Tests GitHub check reviewed if required

Additional context

Testing instructions