chore(qa): clear stale PHPStan baseline entry and PHPUnit deprecations

Two pre-existing findings surfaced during the export-feature test run.
Both are trivial housekeeping, not related to the feature:

- phpstan-baseline.neon: drop the stale ignore for
  RequestInput::wantsJson — the method is now called from the
  helpdesk security-level endpoint and the new export flavor helper,
  so PHPStan no longer matched the pattern and failed with
  `ignore.unmatched` (non-ignorable).

- tests/Service/Auth/SsoUserLinkServiceTest.php: replace the deprecated
  isType('array') / isType('string') assertions with the
  PHPUnit 13-compatible isArray() / isString() equivalents.

Gates after cleanup: PHPUnit 1880 OK (0 deprecations), PHPStan 0 errors.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Service/Auth/SsoUserLinkServiceTest.php

@@ -688,14 +688,14 @@ class SsoUserLinkServiceTest extends TestCase
         $userWriteRepo = $this->createMock(UserWriteRepositoryInterface::class);
         $userWriteRepo->expects($this->once())
             ->method('updateProfileFieldsFromSso')
-            ->with(60, $this->isType('array'))
+            ->with(60, $this->isArray())
             ->willReturn(true);
 
         $avatarService = $this->createMock(UserAvatarService::class);
         $avatarService->expects($this->any())->method('isValidUuid')->with('user-uuid-60')->willReturn(true);
         $avatarService->expects($this->once())
             ->method('saveBinary')
-            ->with('user-uuid-60', $this->isType('string'), 'image/jpeg')
+            ->with('user-uuid-60', $this->isString(), 'image/jpeg')
             ->willReturn(['ok' => true]);
 
         $tenantSsoService = $this->createMock(TenantSsoService::class);