Add automatic default value for char-type field

char type fields are auto-initialized with '\0' when not specified.

Ignore-AOSP-First: security fix
Bug: 206718630
Test: aidl_unittests
Merged-In: I15cfe2a90c0c9adca1692d9a9c997901b90bbbb6
Change-Id: I15cfe2a90c0c9adca1692d9a9c997901b90bbbb6
(cherry picked from commit f04d003b4f5fa9f8ee73b6b560c897de45e644cd)
5 files changed