Invoke TelephonyManager#testSetForbiddenPlmns() API with shell permission

The change-id Ie1d08e65049a6198c10db5d267a001acbdabc145 modified the
permission for the API hence invoking with shell permission

Bug: 204719466
Test: cts
Change-Id: Iebcf1017bfd0c82ef6e019019f742e5c23b2a53e
1 file changed