fix(migration): parameterize tenant_model_provider inserts in mysql_migration (#15313)

### Related issues
Closes #15312

### What problem does this PR solve?

`tools/scripts/mysql_migration.py` built batch INSERT SQL for the
`tenant_model_provider` stage using f-strings with raw `llm_factory` and
`tenant_id` values. If either value contained a single quote, migration
SQL could fail; this also created unnecessary SQL-injection risk in the
migration path.

This PR replaces string interpolation with parameterized SQL
placeholders in `TenantModelProviderStage.execute()`. The migration now
safely handles quoted values and executes deterministically across
existing tenant data.