fix(amazonq): generateCompletion pagination is invoked in blocking context

[Will-ShaoHua]

Problem

GenerateCompletion will wait until "ALL" pages are finished and then return. It's supposed to return the first response immediately when it arrives and push/update the remaining suggestions afterward.

Solution

Revert partial unintended changes made in 9bd9d99#diff-5d07606815c684624bb1c126f4e0da3df22fb2b89be24564d203a8b78fd3c1adL92-L107

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[github-actions]

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