feat(analyzer): Add configurable offline mode to EmailRecognizer to prevent external PSL network calls #2447

Is your feature request related to a problem? Please describe.
In strictly offline, air-gapped, or firewalled enterprise environments, EmailRecognizer can trigger unexpected outbound HTTP calls or socket timeouts during validation because tldextract.extract() attempts to fetch/update the latest Public Suffix List (PSL) from publicsuffix.org. (Historically discussed in #1205).

Describe the solution you'd like
Introduce an opt-in offline: bool = False parameter to EmailRecognizer and its YAML configuration schema (EmailRecognizerConfig):

• offline=False (default): Preserves 100% backward compatibility using standard tldextract.extract.
• offline=True: Instantiates tldextract.TLDExtract(suffix_list_urls=()), which strictly uses the snapshot bundled inside the package wheel, completely disabling all external network access.

Describe alternatives you've considered
Overriding validate_result via subclasses or pre-populating container cache directories manually, but having a native, loader-compatible offline: true flag in Presidio provides a clean, zero-workaround solution for air-gapped deployments.

Additional context
I have implemented and tested this locally:

• Unit tests verifying email detection with offline=True.
• Monkeypatch test asserting suffix_list_urls=() is passed to TLDExtract.
• Full YAML validation via EmailRecognizerConfig registered in CONFIG_MODEL_MAP.
• End-to-end RecognizerRegistryProvider test verifying both offline: true and supported_entities mapping/analysis.

I can submit a Pull Request right away if this approach looks good!