Limit the number of key descriptors sent back

In case the number of key descriptors and their content exceeds the
binder transaction size limit, only return a subset that does fit.

This is a temporary fix - long-term fix is to introduce new API that
lets the caller specify the range of aliases to be fetched.

Bug: 222287335
Test: Manual: Generate 100 keys with a 6k characters name each.
Change-Id: I5e8543a25dd9f1bb504fbc23f35779da0a0153b0
1 file changed