<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
This adds a string slice to pcommon, that will be used by the profiles
pdata.
#### Link to tracking issue
Part of #10109.
#### Testing
This is unit-tested.
cc @mx-psi
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Co-authored-by: Pablo Baeyens <pablo.baeyens@datadoghq.com>
Damien Mathieu