fix broken mev indexer

[pk910]

... by actually starting it 😅 + 2 small fixes

[pk910]

tested here: https://dora-holesky.pk910.de/mev/blocks

[pk910]

not ready yet :/
shows proposed blocks as orphaned

[pk910]

ready now :)
problem was related to the new indexer code which updated the proposed status of mev blocks as part of the finalization routine.
the code used the roots of the canonical blocks to update mev blocks, however mev blocks are identified by their EL block hash.
as no block hash matches any of the provided canonical roots, all blocks were marked as orphaned