chore: removing redundant marker condition in example

[Samo8]

Removes double/redundant condition in markers in example project

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation
• I added new tests to check the change I am making
• All existing and new tests are passing.

[jokerttu]

@Samo8 thank you for this PR.
Please run command
melos run format
to fix this issue https://github.com/googlemaps/flutter-navigation-sdk/actions/runs/20775742631/job/59667001795?pr=579

[Samo8]

@jokerttu thanks, done

[jokerttu]

LGTM