Copy tags if we create new Activity in ASP.NET Core listener

[lmolkova]

Changes

Some tags could be populated by users or 1P libraries (codex) on the Activity created by ASP.NET Core.

In some cases we drop this activity to substitute it with proper one (e.g. when we know W3C is not supported by the ASP.NET Core based on version). In this case we need to copy tags as well.

Checklist

• I ran Unit Tests locally.
• CHANGELOG.md updated with one line description of the fix, and a link to the original issue if available.

Notes for authors:

• FxCop and other analyzers will fail the build. To see these errors yourself, compile localy using the Release configuration.

Notes for reviewers:

• We support comment build triggers
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