Deduplicate contract data bumps

[dmkozh]

Currently we just accumulate all the contract data bumps in a vec and apply them one-by-one in Core. This may cause fees to be double-charged and bumps to be overridden. Instead, we should deduplicate bumps by key and only keep the max value.

This could be done either in the host or in core. Host is preferable as it ensures consistent behavior between core and preflight.

[dmkozh]

There are some inconsistencies with how bump duration is computed in core and in host; I'll experiment with moving this logic completely to the host side to avoid such inconsistencies.