SIM Phone Book : Modify insert and delete operations

The following 2 fixes are submitted as part of this change
1. Add empty number check during insert operation to comply
with the 3GPP 51.101 sections
10.5.1 EFADN (Abbreviated dialling numbers) and
10.5.2 EFFDN (Fixed dialling numbers)
2. Add support to delete SIM record which is stored with only
name and no number. Earlier, if record did not contain number,
delete operation was not performed and error was shown to
the user.

Change-Id: I839fb247c612c4aa5e0e56c096897c1e90099bf6
CRs-Fixed: 539346
(cherry picked from commit d136bf5146643319b85a7bc486add92a1e778798)
(cherry picked from commit 9073e2d149871ed7a8bf8615a69b25527eb326e6)
(cherry picked from commit efec7328bb5209b429aaf8c925610b8593b4b733)