chore: Split apply_block and improve instrumentation

[sergerad]

rpc [ 2.63ms | 47.29% / 100.00% ] rpc.service: "store.BlockProducer" | rpc.method: "ApplyBlock" | otel.name: "store.BlockProducer/ApplyBlock"
┕━ apply_block [ 1.38ms | 0.00% / 52.71% ]
   ┝━ validate_block_header [ 416µs | 15.86% ]
   ┝━ compute_tree_mutations [ 257µs | 9.61% / 9.80% ]
   │  ┕━ acquire_inner_read_lock [ 4.96µs | 0.19% ]
   ┝━ store.block_store.save_block [ 40.9µs | 1.56% ] block_num: BlockNumber(15352) | block_size: 357
   ┝━ await_db_readiness [ 8.67µs | 0.33% ]
   ┝━ acquire_inner_write_lock [ 4.88µs | 0.19% ]
   ┝━ apply_block [ 618µs | 8.69% / 23.55% ]
   │  ┝━ insert_block_header [ 85.0µs | 3.24% ]
   │  ┝━ upsert_accounts [ 3.71µs | 0.14% ]
   │  ┝━ insert_scripts [ 15.6µs | 0.59% ]
   │  ┝━ insert_notes [ 17.6µs | 0.67% ]
   │  ┝━ insert_transactions [ 9.12µs | 0.35% ]
   │  ┝━ insert_nullifiers_for_block [ 47.2µs | 1.80% ]
   │  ┝━ acquire_write_lock [ 7.58µs | 0.29% ]
   │  ┝━ prune_history [ 197µs | 1.49% / 7.51% ] cutoff_block: 15302
   │  │  ┝━ prune_account_vault_assets [ 54.6µs | 2.08% ]
   │  │  ┝━ prune_account_storage_map_values [ 35.5µs | 1.35% ]
   │  │  ┕━ prune_account_codes [ 68.1µs | 2.59% ]
   │  ┕━ acquire_done_lock [ 6.92µs | 0.26% ]
   ┝━ acquire_forest_write_lock [ 5.29µs | 0.20% ]
   ┝━ apply_block_updates [ 32.2µs | 0.54% / 1.23% ] block.number: 15352
   │  ┕━ prune [ 18.1µs | 0.69% ] block.number: 15352
   │     ┕━ ｉ [info]:  | return: 0
   ┕━ ｉ [info]: apply_block successful | block_commitment: 0xb7a57cbc8220e82d587dece459bb90ae5f34d60e1ed1888f5c794260228859e2 | block_num: 15352

[sergerad]

@bobbinth I know you mentioned this should technically be in validate_block_header but its here because of the inner lock.