Fix: harden ValidationInfo.data access for Pydantic 2.13 compat

[eakmanrq]

Description

Pydantic 2.13.0 changed ValidationInfo.data and ValidationInfo.field_name to be None (instead of a dict / string) during model_validate_json(). This broke get_dialect() and would break any field validator that accesses info.data when deserializing models from JSON (e.g. snapshot loading, state sync).

This PR:

• Adds a validation_data() helper in sqlmesh/utils/pydantic.py that safely extracts the data dict from a ValidationInfo, dict, or None, returning an empty dict when data is unavailable
• Refactors get_dialect() to use it
• Replaces all direct info.data access across 9 files with validation_data(info)
• Handles info.field_name being None in environment.py and meta.py

Root cause of the CI failure on #5759 — not caused by that PR's changes, but by Pydantic 2.13.0 being released between the last passing main CI run (2.12.5) and the PR CI run (2.13.0).

Test Plan

• test_audit_formatting_flag_serde now passes (was the original failing test)
• All 42 audit tests pass
• All 317 model tests pass
• 123 snapshot tests pass
• 62 web tests pass
• 1432+ core tests pass (excluding pre-existing env-specific failures)
• Ruff lint and format checks clean on all 9 files

Verified Pydantic 2.13.0 behavior with an isolated uv venv test: ValidationInfo.data and field_name are both None for ALL validator modes (not just mode="before") during model_validate_json(). Normal __init__ and model_validate(dict) are unaffected.

Checklist

• I have run make style and fixed any issues
• I have added tests for my changes (if applicable)
• All existing tests pass (make fast-test)
• My commits are signed off (git commit -s) per the DCO

[Copilot]

Pull request overview

Updates SQLMesh’s Pydantic utilities to be compatible with Pydantic 2.13’s ValidationInfo.data behavior during model_validate_json(), preventing failures when deserializing objects that rely on dialect-aware parsing.

Changes:

• Make get_dialect() tolerate ValidationInfo.data is None and fall back to model._dialect.
• Avoid AttributeError when dialect lookup data is missing in field_validator(mode="before") JSON-validation paths.

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