Modal: add extra focus element check

[christianvuerings]

Noticed the following issue when using the Cambio theme:

Cannot read properties of undefined (reading 'focus')

var focusElement = (el) => {
  if (typeof el.focus === "function") {
    el.focus();
  }
};

https://cambly-inc.sentry.io/issues/5098994999/?alert_rule_id=14792676&alert_type=issue&environment=production&notification_uuid=75afccdd-1d2a-42ce-97ea-d90d6d12c677&project=234235&referrer=slack

[changeset-bot]

🦋 Changeset detected

Latest commit: 4611de1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@cambly/syntax-core	Minor
@syntax/storybook	Patch

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Name	Status	Preview	Comments	Updated (UTC)
syntax	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Mar 25, 2024 4:25pm