Added support for transaction.name in an error object to the intake API

[tobiasstadler]

Motivation/summary

Fixes #6529

Checklist

• Update CHANGELOG.asciidoc

How to test these changes

I added unit tests

[mergify]

This pull request does not have a backport label. Could you fix it @tobiasstadler? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-7.x is the label to automatically backport to the 7.x branch.
• backport-7./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[tobiasstadler]

I ran make update this time

[apmmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2021-11-04T09:23:38.985+0000

• Duration: 39 min 27 sec

• Commit: 290b38d

Test stats 🧪

Test	Results
Failed	0
Passed	6258
Skipped	19
Total	6277

🤖 GitHub comments

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[axw]

Whoa, you're quick :) Thank you!

[axw]

/test

[tobiasstadler]

Thank You!

[stuartnelson3]

test plan: ingest an error, verify transaction.name is set

[marclop]

Tested locally ingesting some errors with 8.0.0-dev4 package but we missed adding the transaction.name field mapping to the data stream:

Error detail

Data Stream mapping

[marclop]

Verified this with 42889b4, which contains the linked PR's fix.