Incorrect escaping of double-quotes in iCalendar text values

The Smarty modifier {crmICalText} is currently escaping double-quotes in TEXT values such that, for exmample, the string

Call me "foo".

is represented in an icalendar DESCRIPTION field like so:

DESCRIPTION:Call me DQUOTEfooDQUOTE.

The spec at https://tools.ietf.org/html/rfc2445#section-4.3.11 indicates that double and single need not be escaped at all, as does the example for the DESCRIPTION field (https://tools.ietf.org/html/rfc2445#section-4.8.1.5), so the correct representation would be

DESCRIPTION:Call me "foo".

Note that this is also mentioned tangentially in CRM-14785, which is actually about a slightly different aspect of escaping.