Cherry-pick #19221 to 7.8: [Metricbeat] Remove dedot for AWS tag value

[kaiyan-sheng]

Cherry-pick of PR #19221 to 7.8 branch. Original message:

What does this PR do?

This PR is to remove dedotting when collecting AWS tag value. Only tag keys are dedotted, but keep tag values to be the original.

Why is it important?

For some use cases, tags value may contain dot, such as IPv4 address. There is no need to dedot when storing into ES in json event field value.

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.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related issues

• Closes [MetricBeat]keep tags original value, DeDot is not unnecessary?  #19112

Screenshots

This is before and after comparison for tag value:

[elasticmachine]

Pinging @elastic/integrations-platforms (Team:Platforms)

[elasticmachine]

💚 Build Succeeded

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Build stats

• Build Cause: [Pull request #19251 opened]

• Start Time: 2020-06-17T15:53:04.664+0000

• Duration: 61 min 18 sec

Test stats 🧪

Test	Results
Failed	0
Passed	482
Skipped	48
Total	530