Fix: warning: unnecessary safe call on a non-null receiver of type ___. This expression will have nullable type in future releases

Fixed warnings stemming from use of unnecessary safe calls `?.` on non-nullable types by replacing instances causing warnings with `.` in order to be compatible with future Kotlin releases.

Bug: 237017037

Test: manual testing on bramble device and ran `adb shell am instrument -w com.android.calendar.tests' with results:

com.android.calendar.FormatDateRangeTest:.
com.android.calendar.UtilsTests:..................
com.android.calendar.WeekNumberTest:.
com.android.calendar.widget.CalendarAppWidgetServiceTest:..
Test results for InstrumentationTestRunner=......................
Time: 0.075

OK (22 tests)

Change-Id: I5b9e82170b191b116a34405caf715ca2b13c081d
(cherry picked from commit 5f4c87cabd62da9a9f797e715abed2750fd55660)
Merged-In: I5b9e82170b191b116a34405caf715ca2b13c081d
18 files changed