Chore: Move reflection type registering

[adrien-berchet]

No description provided.

[Copilot]

Pull Request Overview

This PR moves the reflection type registration logic from the central geoalchemy2/types module to the individual dialect files, streamlining the registration process.

• Update connection handling in tests to use connect() instead of begin() while ensuring proper transaction rollback.
• Remove redundant type registration from geoalchemy2/types/init.py and add corresponding registration in SQLite, PostgreSQL, and MySQL dialects.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/conftest.py	Replaces engine.begin() with engine.connect() and adds try/finally blocks to manage transactions and engine disposal.
geoalchemy2/types/init.py	Removes reflection type registration for spatial types to centralize this logic in dialect-specific files.
geoalchemy2/admin/dialects/sqlite.py	Adds type registration for spatial types in SQLite reflection.
geoalchemy2/admin/dialects/postgresql.py	Adds type registration for spatial types in PostgreSQL reflection.
geoalchemy2/admin/dialects/mysql.py	Adds type registration for spatial types in MySQL reflection.