[INS-467] Add IPinfo detector to default detectors list

[mustansir14]

Description:

This PR adds the IPinfo detector to the default detectors list.

Testing:

Unit Tests are passing. Integration tests didn't have the required keys in the GCP vault. Once added, they are passing too.

Corpora Testing:

The detector does not appear in the list.

Checklist:

• Tests passing (make test-community)?
• Lint passing (make lint this requires golangci-lint)?

---

Note

Medium Risk
Adding ipinfo to the default detector set can change scan results and may increase verification traffic to the IPinfo API when verification is enabled, impacting runtime/false positives for some users.

Overview
Enables IPinfo scanning by default by registering &ipinfo.Scanner{} in pkg/engine/defaults/defaults.go and removing DetectorType_IPInfo from the exclusions list in defaults_test.go.

Updates the IPinfo integration test to assert SecretParts is populated and to ignore new/derived detectors.Result fields (primarySecret, SecretParts) when diffing expected results.

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[github-actions]

Corpora Test Results

No detector regex or keyword changes in this PR. Bench skipped.