fix(integrations): Prevent TypeError when integration provider is undefined

[sentry]

This PR addresses a TypeError: Cannot read properties of undefined (reading 'key') occurring in static/app/views/settings/organizationIntegrations/configureIntegration.tsx at line 97.

The original code integration?.provider.key used optional chaining only for the integration object. If integration was defined but its provider property was undefined, attempting to access .key on undefined would throw a TypeError.

The fix involves adding optional chaining to integration.provider as well, changing the expression to integration?.provider?.key. This ensures that if integration.provider is undefined, the expression safely short-circuits to undefined instead of throwing an error.

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Fixes JAVASCRIPT-38KX

_{Comment @sentry <feedback> on this PR to have Autofix iterate on the changes.}