fix ambiguous decimals for prices (#1257)

Brief comments on the purpose of your changes:


*For Dune Engine V2*
I've checked that:

* [ ] I tested the query on dune.com after compiling the model with dbt compile (compiled queries are written to the target directory)
* [ ] I used "refs" to reference other models in this repo and "sources" to reference raw or decoded tables 
* [ ] if adding a new model, I added a test
* [ ] the filename is unique and ends with .sql
* [ ] each sql file is a select statement and has only one view, table or function defined  
* [ ] column names are `lowercase_snake_cased`

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spellbook/models/opensea/ethereum/opensea_ethereum_trades.sql

@@ -5,8 +5,8 @@ evt_tx_hash || '-' || evt_index::string as unique_trade_id,
 'ethereum' as blockchain,
 evt_tx_hash as tx_hash,
 evt_block_time as block_time,
-om.price / power(10, decimals) * p.price AS amount_usd,
-om.price / power(10, decimals) AS amount,
+om.price / power(10, p.decimals) * p.price AS amount_usd,
+om.price / power(10, p.decimals) AS amount,
 om.price AS amount_raw,
 terc20.symbol as token_symbol,
 wam.token_address as token_address,