Add option to drop scrubbed user IP addresses

[juliosuas]

Summary

Fixes #5701 by adding an EventScrubber option to remove user.ip_address instead of replacing it with [Filtered].

This avoids emitting [Filtered] in a field Relay expects to be a valid IP address, while preserving the existing default behavior for backward compatibility. By default, user.ip_address is still scrubbed through the normal scrubber path and keeps the _meta annotation.

Testing

• python -m pytest tests/test_scrubber.py tests/new_scopes_compat/test_new_scopes_compat_event.py -q
• ruff check sentry_sdk/scrubber.py tests/test_scrubber.py
• ruff format --check sentry_sdk/scrubber.py tests/test_scrubber.py
• git diff --check

[sentry]

Bug: Removing user.ip_address via pop instead of letting the scrubber replace it breaks backward-compatibility tests that expect the field to be present and marked as "[Filtered]".
_{Severity: MEDIUM}

Suggested Fix

Revert the logic to allow the scrub_dict function to handle the scrubbing of ip_address. Instead of preemptively removing the key with user.pop("ip_address", None), let the existing scrubbing mechanism process it. This will replace the value with "[Filtered]" and generate the necessary _meta annotations, maintaining backward compatibility.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: sentry_sdk/scrubber.py#L141-L143

Potential issue: When `send_default_pii=False`, the new logic in `EventScrubber`
preemptively removes `user.ip_address` by calling `user.pop("ip_address", None)`. This
occurs before the `scrub_dict` function is executed. As a result, `scrub_dict` never
processes the `ip_address` field, so it is not replaced with `"[Filtered]"` and the
corresponding `_meta` scrubbing annotation is not created. This breaks several
backward-compatibility tests in
`tests/new_scopes_compat/test_new_scopes_compat_event.py` that assert the presence of
the scrubbed value and its metadata.

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[ericapisani]

Thanks for opening a PR! These changes are generally looking good, just one small adjustment before we're good to ship

[ericapisani]

This is the right idea, but let's make one further optimization:

Suggested change

	if isinstance(user, dict) and "ip_address" in self.denylist:
	user.pop("ip_address", None)
	if "ip_address" in self.denylist and isinstance(user, dict):
	user.pop("ip_address", None)

By moving the "ip_address" in self.denylist earlier in the conditional and evaluating it first, it means that we can ignore the second condition if the first isn't satisfied.