[BCI-3862][chainlink-common] - Change DSL Block primitive to string instead of int

[Farber98]

Task Description:

Change ChainReader block DSL uint64 type to string and update EVM implementation to reflect changes

This PR:

Changed the block proto field and fixed all the reference failures within chainlink-common.

Ticket:

• BCI-3862

Unblocks:

• [BCI-3862][chainlink] - Change DSL Block primitive to string instead of int chainlink#14033

Note:

• Previously was [BCI-3862][chainlink-common] - Change DSL Block primitive to string instead of int #683, but commits where not signed