Add support for the Global Profile API

[tholovina-sift]

Add support for the Global Profile API

Summary

Sift is launching a new "Global Profile API" that returns cross-tenant identity,
decision, chargeback, order, transaction, and location signals for a user. This PR
adds client support for both of its endpoints, following the existing
FieldSet / SiftRequest / SiftResponse conventions used throughout this SDK
(e.g. GetDecisionsRequest, GetMerchantRequest, ApplyDecisionRequest).

What changed

New endpoints

• GET /v3/accounts/{accountId}/global_profile/users/{userId}
  • GlobalProfileFieldSet (src/main/java/com/siftscience/model/GlobalProfileFieldSet.java) —
    carries userId (path) plus optional globalOnly / includeOwnData query params.
  • GlobalProfileRequest / GlobalProfileResponse — GET request following the
    GetDecisionsRequest query-parameter pattern (only sets global_only /
    include_own_data on the query string when explicitly provided, letting the
    server apply its own defaults otherwise).
• POST /v3/accounts/{accountId}/global_profile/lookup
  • GlobalProfileLookupFieldSet (src/main/java/com/siftscience/model/GlobalProfileLookupFieldSet.java) —
    JSON body with email / phone. Overrides validate() (same pattern as
    ApplyDecisionFieldSet) to throw MissingFieldException client-side if
    both are missing, so callers get a clear error before any network call.
  • GlobalProfileLookupRequest / GlobalProfileLookupResponse.
• SiftClient gains two new buildRequest(...) overloads for the field sets
  above, matching the existing dispatch-by-type convention.

Response model

Both endpoints share GlobalProfileResponseBody (extends BaseResponseBody,
adds error_code, lookback_months, and nested objects), plus new supporting
model classes: GlobalProfileSummary, GlobalProfileIdentityAge,
GlobalProfileUserDecisions, GlobalProfileChargebacks, GlobalProfileOrders,
GlobalProfileTransactions, GlobalProfileLocations, and
GlobalProfileLocationAccount. All use the repo's @Expose/@SerializedName
Gson convention. When profile_summary.identity_found is false, all other
fields are null, as documented in the Javadoc on GlobalProfileResponseBody.

Tests

• GlobalProfileTest — GET happy path with both query params set, GET with no
  optional params (verifies they're omitted from the URL), and an
  identity_found: false case verifying the other fields deserialize to null.
• GlobalProfileLookupTest — POST lookup by email, POST lookup by phone
  (asserts request body), and a client-side validation test asserting
  MissingFieldException is thrown when neither email nor phone is set.

All tests use the existing MockWebServer + OkHttpUtils.urlRewritingInterceptor

• JSONAssert pattern used by the rest of the test suite.

Docs

• CHANGES.MD: new 3.23.0 entry (minor bump for the new feature).
• build.gradle: version bumped to 3.23.0.
• README.md: new "Global Profile API" section with usage examples for both
  endpoints, following the style of the existing "Decision Status API" section.

Error handling

No changes were needed to SiftRequest's error-handling switch — the
documented error codes (52 UNAUTHORIZED, 53 PERMISSION_DENIED /
ENTITLEMENT_REQUIRED, -4 RATE_LIMIT_EXCEEDED, 51 INVALID_API_KEY, 55
INVALID_PARAMETER, -1 SERVER_ERROR) are already mapped to the appropriate
SiftException subclasses there.

Testing done

• Manually reviewed all new/changed files against the existing patterns in
  GetDecisionsRequest/GetDecisionFieldSet, ApplyDecisionRequest/
  ApplyDecisionFieldSet, GetMerchantRequest, SiftRequest, SiftResponse,
  FieldSet, and BaseResponseBody to keep naming, serialization, and
  validation conventions consistent.
• Added new unit tests (GlobalProfileTest, GlobalProfileLookupTest)
  covering both endpoints, optional query params, the identity_found: false
  response shape, and client-side validation of the lookup endpoint's
  required-field rule.
• Could not run ./gradlew build/./gradlew test in this sandbox: the
  Gradle wrapper needs to download the Gradle 8.14 distribution and
  dependencies over the network, which is unavailable here. No compiler
  errors were spotted during manual review, but a real CI run (e.g. via
  /jenkins-test on the PR) is recommended before merge.