fix(cli): make sure to await returned promise from async functions

[fossamagna]

Description of changes

• make sure to await returned promise from deleteResourceFiles.
• make sure to await returned promise from emitError.
• change to empty object form empty array as default value of questionOptions.serviceDeletionInfo
• Increase test coverage of amplify-cli/extensions.

Issue #, if available

lerna --scope @aws-amplify/cli run test

Description of how you validated changes

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Merging #7379 (62481a8) into master (3dbb3bf) will increase coverage by 0.15%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #7379      +/-   ##
==========================================
+ Coverage   52.72%   52.87%   +0.15%     
==========================================
  Files         513      514       +1     
  Lines       25914    25998      +84     
  Branches     5058     5074      +16     
==========================================
+ Hits        13662    13746      +84     
  Misses      11286    11286              
  Partials      966      966              

Impacted Files	Coverage Δ
.../src/extensions/amplify-helpers/remove-resource.ts	100.00% <100.00%> (ø)

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[ammarkarachi]

@fossamagna thank you for your contribution! I will review this and get back to you

[github-actions]

👋 Hi, this pull request was referenced in the v5.0.2 release!

Check out the release notes here https://github.com/aws-amplify/amplify-cli/releases/tag/v5.0.2.