Camera metadata: Check source metadata size

Source size passed by client could be smaller than 'camera_metadata_t'.
In this case the cast in 'allocate_copy_camera_metadata_checked()' will
be incorrect and we will try to access invalid heap memory.

Bug: 67782345
Test: Camera CTS
FPIIM-2319
Change-Id: I9582c704f414493978d09ffb603b5e8368cda5ce
(cherry picked from commit 489bbd13bf0add8029444b9d9505b3d118776ea3)
1 file changed