Add pii around upn for wp registration web response

[kaisong1990]

Proposed changes

Add PII around upn

Type of change

• Feature work
• Bug fix
• Documentation
• Engineering change
• Test
• Logging/Telemetry

Risk

• High – Errors could cause MAJOR regression of many scenarios. (Example: new large features or high level infrastructure changes)
• Medium – Errors could cause regression of 1 or more scenarios. (Example: somewhat complex bug fixes, small new features)
• Small – No issues are expected. (Example: Very small bug fixes, string changes, or configuration settings changes)

Additional information

[azure-pipelines]

This pull request does not update changelog.txt.

Please consider if this change would be noticeable to a partner or user and either update changelog.txt or resolve this conversation.

[oldalton]

We shouldn't use _PII_NULLIFY for actual code, since we rely on user info as part of the flow. We should only do _PII_NULLIFY in logs

[kaisong1990]

Hi @oldalton do we need to check into this release or if we can wait till the next one?

[kaisong1990]

We shouldn't use _PII_NULLIFY for actual code, since we rely on user info as part of the flow. We should only do _PII_NULLIFY in logs

Hi @oldalton I benchmarked the performance, and the difference is below 1 ms. The NSRange solution is slightly better, and it is currently used in MSIDMaskedUsernameLogParameter so I switched with the similar logic