refactor: toggle theme on DOM load

[alexbarnsley]

Summary

https://app.clickup.com/t/861mrtzmx

initial toggleTheme() call is necessary to avoid flickering when the page loads, this new one is necessary for the case where livewire was not loaded yet and we want to dispatch the event

Checklist

• I checked my UI changes against the design and there are no notable differences
• I checked my UI changes for any responsiveness issues
• I checked my (code) changes for obvious issues, debug statements and commented code
• I provided a screenshot of my changes to the component (if applicable)
• I regenerated the icons.html file and checked if my newly added icon is shown correctly (if necessary)
• I added an explanation on how to use the component to the readme (if necessary)
• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged