Fix reversion of RRULE UNTIL behavior

Prior to 0.1.25, ics files containing events like the following worked normally.  [A change](11dfa8c64c (diff-6659079db1c5e26c4bd075f64b432522644ff3ee3bd4264f2863bd6f69d63e72L287-R405)) in the 11dfa8c64c caused these to break.  This is an ics I'm getting from Google for my scheduled lunches :)

This restores the pre-0.1.25 behavior and continues to pass all tests.

```
BEGIN:VEVENT
SUMMARY:LUNCH
DTSTART;TZID=America/Boise:20210929T130000
DTEND;TZID=America/Boise:20210929T135000
DTSTAMP:20211029T005456Z
UID:not_sure_if_this_uid_is_secret@google.com
SEQUENCE:3
RRULE:FREQ=WEEKLY;UNTIL=20211020;BYDAY=MO,TH,WE;WKST=SU
EXDATE;TZID=America/Boise:20211013T130000
CREATED:20210811T153934Z
DESCRIPTION:
LAST-MODIFIED:20210927T184338Z
LOCATION:
STATUS:CONFIRMED
TRANSP:OPAQUE
X-APPLE-TRAVEL-ADVISORY-BEHAVIOR:AUTOMATIC
BEGIN:VALARM
ACKNOWLEDGED:20210830T185450Z
ACTION:NONE
TRIGGER;VALUE=DATE-TIME:19760401T005545Z
UID:343EB08E-9C4C-4151-92D0-80B351A080B2
X-WR-ALARMUID:343EB08E-9C4C-4151-92D0-80B351A080B2
END:VALARM
END:VEVENT
```

icalevents/icalparser.py

@@ -457,12 +457,9 @@ def parse_rrule(component, tz=UTC):
             rdtstart = normalize(rdtstart, tz=tz)
 
         # Remove/add timezone to rrule until dates depending on component
-        if type(rdtstart) is date:
-            for index, rru in enumerate(rrules):
-                if "UNTIL" in rru:
-                    rrules[index]["UNTIL"] = adjust_timezone(
-                        component, rru["UNTIL"], tz
-                    )
+        for index, rru in enumerate(rrules):
+            if "UNTIL" in rru:
+                rrules[index]["UNTIL"] = adjust_timezone(component, rru["UNTIL"], tz)
 
         # Parse the rrules, might return a rruleset instance, instead of rrule
         rule = rrulestr(