fix: keep amp accuracy in enrichment

[johngrantuk]

Updating test block number in #73 leads to existing tests failing. For the new block a different swap path is being found. The new CS amp value is such that the loss of accuracy during enrichment leads to errors during future calculations.

• Update block no in test to replicate issue seen in Update balancerPoolDataQueries to latest contract code #73
• Update amp parsing during enrichment
• Update OnChainPoolDataEnricher config in test to load Amp for ComposableStable pools because SG value was incorrect (Maybe this should be a default?)