Change regular expression format of serial number

CDD for serial's format of regular expression was changed since
android 8.1. but related tests are not adapted.

Bug: 265833518
Test: run cts -m CtsTelephonyTestCases, CtsUsbTests
Change-Id: Ie5e6619839d2c6dd97576ae5c3eb242d976503c0
(cherry picked from commit e5c7a5c91d0437afcb2d453d8014b2824d0a9752)
2 files changed