Increase coverage fix bugs

[aspacca]

Bug

What does this PR do?

Increase coverage of the whole codebase to 100%

Why is it important?

Extending the coverage to 100% avoided making assumptions on execution paths worth covering or not.
Aiming for 100% in a mix between unit and integration tests, we were able to assure nothing was missed because of "bias" on what was worth covering and what not, and indeed we spotted three bugs that we were able to fix:

1. flushing in kinesis-data-stream input type
2. empty messages in include exclude filters
3. empty lines in JsonCollector decorator

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
  - [ ] I have made corresponding changes to the documentation
  - [ ] I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.md

Author's Checklist

• [ ]

How to test this PR locally

Related issues

Use cases

Screenshots

Logs

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2022-04-21T04:03:10.498+0000

• Duration: 24 min 35 sec

Test stats 🧪

Test	Results
Failed	0
Passed	65
Skipped	0
Total	65

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.