Revert "Need to check empty not null for String"

This reverts commit 77680bd4dbf69fe22a41b73c479096bd418aac8a.

Reason for revert: this change caused no wcdma signal bar because "" is a valid default value from carrier config

Bug: 118800169
Change-Id: I0285827c84edda88f7f0d287d254ba89c9931382
1 file changed