Set tech for incoming messages correctly

In case of SOURCE_NOT_INJECTED, the SMS tech will be set based on SMS
format. Otherwise, it will be either SOURCE_INJECTED_FROM_IMS or
SOURCE_INJECTED_FROM_UNKNOWN according to the smsSource.
It updates descriptions about SMS format also.

Bug: 182194827
Test: build

Signed-off-by: Taesu Lee <taesu82.lee@samsung.com>
Change-Id: I5ccdd00cd36ee0965373b158f1dc848c090c22f7