Fixing double conversion of time between UTC and local timezone

[chamakura]

• Does the pull request solve a related issue?
  Yes

• If so, can you reference the issue?
  All events in standard calendar module are shown in UTC following the update to MM 2.12.0 #2068

• What does the pull request accomplish? Use a list if needed.
  Event times appear to be broken in the current release. This fix removes the logic in two places that's converting across UTC and local timezones. I haven't updated the Changelog, but can do it if this seems reasonable.

• More context
  I suspect this to be case because we started using 'ical' directly, and some of the changes made in PR 1884 in 'ical' might have been lost. I had submitted a fix to 'ical' to correctly handle timezone parsing (Fix to correctly handle date-times when timezone Id is provided peterbraden/ical.js#111), but it's not accepted as there's a build dependency.
  I will try to submit a separate fix outside of 'ical' to correctly handle timezone conversion when the event organizer is in a different timezone.

• If it includes major visual changes please add screenshots.
  It worked for my Calendar which has some pretty complex events.

[MagicMirrorBot]

	Warnings
⚠️	Please include an updated CHANGELOG.md file. This way we can keep track of all the contributions.

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