By Martin Baccardax Soaring wages, shipping rates and Covid costs are likely to eat away at Amazon’s Q4 bottom line, but the world’s biggest online retailer is still a top-line powerhouse. Amazon (AMZN) – Get Amazon.com, Inc. Report shares slumped lower Thursday ahead of a key fourth quarter earnings report for the world’s largest online retailer that is likely to focus on labor costs and e-commerce growth. Amazon, which looks to have held onto the massive gains in market share is gathered during the pandemic, is finding the cost of that maintenance increasing: wage increases and fulfilment ce…