Update awsappsignals processor README

[lisguo]

Update awsappsignals processor README to include "Application Signals" instead of "AppSignals"

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Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

[github-actions[bot]]

This PR was marked stale due to lack of activity.

[github-actions[bot]]

This PR was marked stale due to lack of activity.