[MWPW-195675] : Add clone event flow with Marketo integration dialogs

[sharmeebuilds]

Summary

• Extracts all clone logic from EventsDashboard into a dedicated CloneEvent component
• Single dialog with step-based content (no stacking modals) — steps through name entry, then conditional Marketo flow based on event type/cloud
• DX in-person (ExperienceCloud + InPerson): prompts "Do you need Marketo integration?" → optional Marketo config form (5 fields)
• ExperienceCloud webinar: prompts for Marketo form URL/ID
• CreativeCloud events (any type): clone directly after name entry
• Validates event name against existing names with inline error state
• Disables all buttons during pending API call to prevent duplicate submissions
• Deduplicates Marketo option constants by exporting from MarketoIntegrationComponent
• Uses S2 style() macro font token for headings; small muted dialog title

Test plan

• Clone a DX in-person (ExperienceCloud) event — verify Marketo prompt appears, Yes shows config form, No clones without Marketo
• Clone an ExperienceCloud webinar — verify Marketo ID dialog appears
• Clone a CreativeCloud event (any type) — verify clones directly after name entry
• Enter a duplicate event name — verify "This name is already taken" error and Continue is disabled
• Click No on Marketo prompt — verify button shows spinner and all buttons disable
• Lint + type-check pass (npm run check)

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