fix(analyzer): use valid region code GB instead of UK in PhoneRecognizer

[developer0hye]

Change Description

Fixes #2173.

PhoneRecognizer.DEFAULT_SUPPORTED_REGIONS contained "UK", which is not a valid region code in the phonenumbers library (Google libphonenumber). Region codes are ISO 3166-1 alpha-2, where the United Kingdom is "GB".

Because "UK" is not a real region, that entry was a no-op, and UK numbers in national/local format were never detected with the default configuration. Only international-format +44 … numbers matched — those carry the country code and match under any region, which is why the gap went unnoticed (the existing +44 (20) 7123 4567 test passes for exactly this reason).

>>> import phonenumbers
>>> "UK" in phonenumbers.SUPPORTED_REGIONS
False
>>> phonenumbers.country_code_for_region("UK")
0
>>> phonenumbers.country_code_for_region("GB")
44

Detection of a national-format UK number, before vs. after:

text	before ("UK")	after ("GB")
020 7946 0958 (London landline)	not detected ❌	detected ✅
07911 123456 (mobile)	not detected ❌	detected ✅
+44 7911 123456 (international)	detected ✅	detected ✅

Changes

• phone_recognizer.py: replace "UK" with "GB" in DEFAULT_SUPPORTED_REGIONS.
• test_phone_recognizer.py: add a regression test for a national-format UK number (020 7946 0958).
• CHANGELOG.md: document the fix under [unreleased] → Analyzer → Fixed.

How Has This Been Tested?

• pytest tests/test_phone_recognizer.py — 27 passed (including the new case).
• ruff check presidio-analyzer/presidio_analyzer — all checks passed.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (CHANGELOG)
• My changes generate no new warnings
• I have added tests that prove my fix is effective
• New and existing unit tests pass locally with my changes

[Copilot]

Pull request overview

This PR fixes a correctness gap in Presidio Analyzer’s PhoneRecognizer default configuration by switching the invalid libphonenumber region code "UK" to the valid ISO 3166-1 alpha-2 code "GB", restoring detection of UK national-format phone numbers under default settings.

Changes:

• Updated PhoneRecognizer.DEFAULT_SUPPORTED_REGIONS from "UK" to "GB".
• Added a regression test ensuring a UK national-format number (020 7946 0958) is detected with defaults.
• Documented the fix in the Analyzer “Fixed” section of CHANGELOG.md.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
presidio-analyzer/presidio_analyzer/predefined_recognizers/generic/phone_recognizer.py	Replaces invalid default region "UK" with valid "GB" to enable UK national-format matching.
presidio-analyzer/tests/test_phone_recognizer.py	Adds a regression case proving UK national-format numbers are detected with the corrected default regions.
CHANGELOG.md	Records the behavior change/fix under [unreleased] → Analyzer → Fixed.