Create alias for `processThreadBreadcrumbIntegration` called `childProcessIntegration`

[lforst]

Description

• Create an alias called childProcessIntegration
• Deprecate processThreadBreadcrumbIntegration
• Update docs

[github-actions]

A PR closing this issue has just been released 🚀

This issue was referenced by PR #14334, which was included in the 8.39.0 release.