Downloaded ICS file is invalid

[smncd]

Hey! Been playing around with Rallly and really impressed so far!

I noticed that the content of the ICS file that you can download after a poll is finalized is url encoded (data:text/calendar;charset=utf8,BEGIN:VCALENDAR%0D%0AVERSION:2.0 [...]).
Due to this, the file can't be imported, or at least it does not work when I've tried it with Proton- and Google calendar.

When trying to pinpoint the issue, I came across this: https://github.com/lukevella/rallly/blob/main/apps/web/src/components/add-to-calendar-button.tsx#L125. Creating a blob here means that the url encoded string is what gets put in the downloaded ics file.

Happy to open a PR for this if you're interested.

Cheers!

To Reproduce
Steps to reproduce the behavior:

1. Create poll
2. Mark as completed
3. Download ICS file
4. Try to add to your calendar of choice, or open as plaintext.

[smncd]

Actually, seems it was a pretty easy fix. PR here: #1390