Fixed bug with title >255 characters not showing up on EWS calendar

[aiirwiick]

Background

Fixed EWS calendar title length bug where the event wouldn't be created if a user submitted an event with a title >255 characters through Nylas API
https://app.clubhouse.io/nylas/story/18334/event-with-a-title-255-characters-accepted-on-nylas-but-failed-to-create-on-ews-calendar

Implementation

Changed 'subject' attribute to TextField class instead of CharField class in items.py

Tests

Tested local exchangelib by trying to create calendar events with titles >255 on test account

[shortcut-integration]

This pull request has been linked to Clubhouse Story #18334: Event with a title >255 characters accepted on Nylas but failed to create on EWS calendar.

[ecederstrand]

Hi @aiirwiick

I don't think this is a good solution because EWS actually only supports subjects up to 255 chars. You will find that if you create items with a longer subject, EWS will truncate the subject at 255 chars, adding a ... at the end if it was truncated.

I think it's better to handle excessive subject lengths in the part of your own code that creates the CalendarItem.