libbinder_rs: Remove Vec<MaybeUninit<T>> from parcelable.rs

Vec<MaybeUninit<T>> leaks elements if it was partially initialized
and we got an error. Replace it with a safer Vec<UninitType<T>> which
uses either Default or Option::None to initialize elements.

Bug: 278648274
Test: atest atest_integration_test
Change-Id: I2ec97a17b215cb875a48e894eb04832e8a967fca